weak but significant distortion at three linked loci on chromosome Tgu2 and we were able to replicate this finding in each of two follow-up datasets (overall transmission ratio = 0.567, 95% CI = 0.536-0.600, based on 1,101 informative meioses). Although the driving allele was preferentially transmitted by both heterozygous females (ratio = 0.560, 95% CI = 0.519-0.603) and heterozygous males (ratio = 0.575, 95% CI = 0.531-0.623) we could rule out (early) viability selection and biased gene conversion as possible mechanisms, because the bias remained the same in clutches in which all eggs were analyzed (ratio = 0.564, 95% CI = 0.521-0.606) and could be verified over several megabases. Thus, we here describe a prezygotically active segregation distorter operating equally effectively in female and male meioses.

Poster session B - MAX 412

# Retrotransposon-mediated origin of loci functioning under alpine conditions in the autotetraploid Biscutella laevigata (51795)

Rimjhim Roy Choudhury, Christian Parisod.

*University of Neuchâtel.*

Transposable elements (TEs), long considered as junk DNA, harbor regulatory sequences potentially affecting host genes in response to stresses and environmental challenges. Accordingly, bursts of TE activity after whole genome duplication (WGD) events may have a substantial evolutionary impact by fostering the origin of phenotypic novelties and supporting lineage diversification. In this study, we explore the hitchhike of TE sequences in duplicated genomes and their co-option for plant regulation to stress response. We focus on functional TE-gene sequences in natural populations of the alpine mustard Biscutella laevigata, including highly dynamic autopolyploid genomes and their diploid progenitors. We thus mined the transcriptome of B. laevigata to characterize putatively functional TE-gene co-transcripts and, out of 530 TE transcripts, we identified 17 chimeras joining large gene and TE parts. These transcripts were highly expressed as compared to random TE insertions and mostly contain element binding sites having potential relation with drought and cold challenges in alpine areas. Genotyping across populations and other Brassicaceae highlight their origin and evolution. Further studies linking genotype to phenotype will bring significant advances in our understanding of the mechanisms generating evolutionary-relevant variation from burst of transposition.

Poster session B - MAX 412

# Revisiting the selfish conflict theory of mitochondrial inheritance (51862)

Joshua Christie, Timothy Schaerf, Madeleine Beekman.

*The University of Sydney.*
For almost four decades, uniparental inheritance of mitochondria (UPI) has been explained by the selfish conflict theory. This hypothesis states that UPI evolved to prevent the spread of selfish mitochondria, which replicate quickly but produce energy inefficiently. UPI is thought to prevent the spread of selfish mitochondria by causing segregation of such mitochondria into unfit cells that are purged from the population. UPI, however, so efficiently purges selfish mitochondria that it is subject to negative frequency-dependent selection: when UPI is common, selfish mutants are rare; when selfish mutants are rare, UPI is no longer advantageous. As a result, UPI does not go to fixation in mathematical models under realistic assumptions. Clearly, we require a new explanation for UPI that is consistent with population genetic theory. Empirical evidence may hold the key. It has recently been shown that merely mixing two different but normal mitochondrial haplotypes within a cell (heteroplasmy) can cause dysfunction. Using a mathematical model, we show that selection against heteroplasmy can lead to the evolution of UPI under a wide variety of assumptions and parameter values. Thus, we suggest that selection against heteroplasmy explains the evolution of UPI.

## The evolution of metazoan genomes and highly conserved SINE domains (51881)

**Andrea Luchetti**, Eva Satovic, Miroslav Plohl, Barbara Mantovani.

*Department of Biological, Geological and Environmental Sciences - University of Bologna;*
*Division of Molecular Biology, Ruder Boskovic Institute - Zagreb.*

Short interspersed elements (SINEs) are non-autonomous retrotransposons with modular structures: a small RNA-related head, a body and an AT-rich tail. Despite their high turnover rate and de novo emergence, the body may retain highly conserved domains (HCD) among different SINE families: in metazoan, up to seven HCD-SINEs have been recognized. Interestingly, two HCD-SINEs (CORE- and Deu-SINEs) have been repeatedly subject to exaptation in mammalian genomes, becoming part of gene regulatory networks. Analyzing molluscan transcriptomes and genomic sequences we characterized four new HCD-SINE families, whose insertion site analyses suggest recent activity. Two HCDs were previously found in chordates' SINEs: the V-domain (here found in gastropods, bivalves and chitons), and the CORE-domain (here found in bivalves and gastropods). A CORE-SINE has been further identified in the horseshoe crab and one more family isolated in snails retains the cephalopods' Ceph domain. Tracking the ancestry of HCDs in the metazoan phylogeny revealed that some of them date back to the Radiata-Bilateria and the Protostomia-Deuterostomia splits. We suggest that the evolutionary conservation of HCD may account for the high SINE diversity ("module exchange" model) and for their long-term inheritance in metazoan genomes.

## Horizontal gene spread through bacterial host altruism (51971)
**Tatiana Dimitriu**, Dusan Misevic, Sam Brown, Ariel Lindner, Francois Taddei.

*Imperial College London; Institut National de la Santé et de la Recherche Médicale; University of Edinburgh.*

In bacteria, plasmids and other mobile genetic elements often confer crucial phenotypes such as antibiotic resistance, providing strong benefits to their hosts. However, the fitness consequences of horizontal transfer itself are less clear. Indeed, transfer can be interpreted as a parasitic trait because of its costs to the host, but also as a trait benefiting host populations through the sharing of a common gene pool. Here we show that costly plasmid donation is an altruistic act when it spreads beneficial genes, and can be specifically maintained by kin selection mechanisms. We first show mathematically that donor ability can be selected when relatedness among donors and recipients is high, ensuring high frequency of transfer towards kin. We further experimentally demonstrate that sufficiently high relatedness can be achieved through either kin discrimination or population structure, both mechanisms being likely to occur in natural environments. Our work shows that horizontal gene transfer can be promoted by bacterial hosts themselves and not only by mobile genetic elements. Moreover, preferential transfer among kin combined with the fitness benefits brought by beneficial plasmids can lead to a mutualistic association between high transfer strains and beneficial plasmids.

Poster session B - MAX 412

# PGE in the citrus mealybug: is the maternal victory complete? (52156)

**Andrés G. de la Filia**, Laura Ross.

*Institute of Evolutionary Biology, The University of Edinburgh.*

Genetic conflict has been brought up to explain the striking diversity of genetic systems. Among these, paternal genome elimination (PGE) is found in several insects, including citrus mealybugs (Planococcus citri). In males, the paternally inherited genome, under control of the maternal half, is first heterochromatinized and discarded later during spermatogenesis. PGE is therefore a whole-genome form of meiotic drive, as sperm only contain maternally inherited chromosomes. However, paternal genomes can sometimes escape germ-line elimination and/or silencing, suggesting an evolutionary arms race between maternal and paternal genomes. This study investigates if paternal genomes have evolved adaptations against PGE that could be unveiled by exposing paternal genotypes to different maternal backgrounds by analyzing F1 and F2 of intraspecific and interspecific crosses (with P. ficus). Paternal line inheritance was assessed via microsatellite analysis, while transcriptome data for whole F1 males and F1 testis samples was generated to evaluate whether paternal alleles can escape inactivation and if expression patterns differ in testes. Our results provide a solid ground to study potential PGE suppressors and thus increase our knowledge of how PGE is maintained and lost, eventually casting more light on the involvement of male-female conflict in the evolutionary dynamics of genetic systems.
# Dynamics of transposable elements in the genome of Taraxacum officinale apomictic lineages. (52214)

**Julie Ferreira de Carvalho**, Peter Van Dijk, Koen Verhoeven.

*Netherlands Institute of Ecology (NIOO KNAW), Wageningen, The Netherlands; Keygene, Wageningen, The Netherlands.*

Asexual species are considered as evolutionary dead-ends with reduced probability of fixing advantageous mutations and enhanced accumulation of deleterious mutations due to inefficient purging. Therefore, active transposable elements (TE) might accumulate in asexual lineages, which could be further promoted if TE silencing mechanisms associated with meiosis and gametogenesis are circumvented in asexuals.

To gain more insight into the dynamics of TEs under asexuality, we used apomictic dandelions as a model system to evaluate: (1) TE activity differences during gametogenesis and plant development and (2) the involvement of TEs in early evolutionary divergence between plants from a single apomictic lineage. We used an RNA-Seq approach, comparing gene expression levels between reproductive cells and somatic tissue and between leaf tissues of five apomictic natural accessions sampled around Central Europe.

Our results suggest main differences in the level of gene expression between reproductive cells and vegetative tissue suggesting activation of TEs coupled with activation of silencing enzymes during gametogenesis. Heritable gene expression differences between apomictic clone members were dominated by TEs and TE associated genes. Specifically, some protein domains (transposase and transcriptase-like proteins) are differentially expressed between clone members suggesting a possible role in early stages of evolutionary divergence in this species.

Poster session B - MAX 412

# Transposable element dynamics mediated by piRNA pathway in response to environmental changes (52345)

**Marta Marialva.**

*Instituto Gulbenkian de Ciência.*

Heritable phenotypic variation is the raw material for evolution by natural selection. To fully understand evolutionary change, we must study the processes that drive the formation of new genetic variants. Transposable elements, genomic sequences with the ability to move, are an important source of adaptive genetic variation. In order to understand what make transposable elements move we explored to what extent biotic and abiotic environmental factors impact their activity during Drosophila melanogaster oogenesis. It is known that environmental stresses can induce transposon jumping, and that the piRNA pathway inhibits transposition in the germline. We connected these two observations by looking at the expression of transposons and at piRNA pathway activity in the germline of females under different environmental conditions. We concluded that abiotic (temperature) and biotic (symbiont) factors affect transposable element activity synergistically, and propose that Piwi, a key protein in the piRNA pathway, mediates those responses.
# Parasitic plasmids increase bacterial mutation rates and antibiotic resistance (52357)

Fredrik Inglis, Jenna Gallie, Martin Ackermann.

*Washington University in St. Louis; ETH Zurich; ETH Zurich.*

Plasmids play a pivotal role in bacterial evolution and ecology, acting as reservoirs of genetic material that allow for rapid adaptation to novel environments. However, as many bacteria inhabit fluctuating environments, under various environmental conditions plasmids may provide little or no benefit to their host cell, and because there is often a fitness cost associated with plasmid carriage, they should be selected against. Under these conditions plasmids no longer act as beneficial sources of genetic information, but can instead be viewed as genetic parasites exploiting their bacterial host. It has previously been shown that coevolution with parasites is an important evolutionary factor that can drive rapid and extensive changes in both host and parasite. As bacteria are constantly evolving in the presence of plasmids, we were curious to investigate how bacteria respond when coevolving with a parasitic plasmid. After coevolving Escherichia coli carrying a ColE1-type plasmid for 120 generations, we found that mutations in two different bacterial genes caused a drastic loss in plasmid carriage. Interestingly mutations in these two genes also conferred high levels of antibiotic resistance through an increase in bacterial mutation rate and changes to RNA polymerase. This suggests that mutations associated with plasmid carriage and loss can lead to large pleiotropic effects in the host.

# Evolutionary dynamics of meiotic drive elements in the fungus Podospora anserina (52565)

Eric Bastiaans, Duur K. Aanen, Alfons J. M. Debets, Jesper Svedberg, Hanna Johannesson.

*Uppsala University; Wageningen University.*

Natural selection may favour selfish genetic elements in the genome that harm the individuals carrying them. One class of such selfish genetic elements consists of meiotic drivers, also referred to as segregation distorters. Although meiotic drive is widespread in nature and has been identified in a wide range of eukaryotes, there is a profound lack of empirical insight into the evolutionary causes and consequences of this phenomenon.

We introduce the ascomycete fungus Podospora anserina as a novel system for the study of the evolutionary dynamics of meiotic drive. In P. anserina several meiotic drive elements that cause spore killing are present at a high frequency in natural populations. Spores carrying the Spore killer allele inhibit the development of spores not carrying the allele. We are using six different Spore killers found in a large collection of natural isolates from the Netherlands to study the dynamics of Spore killing. We will combine experimental and genomic approaches
to I) Identify the six yet unidentified Spore killer elements of P. anserina, II) Investigate the evolutionary dynamics of the different Spore killers by comparative genomics, and III) Experimentally investigate population biology of Podospora Spore killers, i.e., under which conditions they may invade a population.

## Differential introgression of retrotransposons in a natural hybrid zone between wild wheats (52670)

Natacha Senerchia, **François Felber**, Christian Parisod.

*University of Neuchâtel; Musée et Jardins botaniques cantonaux vaudois.*

Interspecific hybridization leads to new interactions among divergent genomes, revealing the nature of genetic incompatibilities having accumulated during and after the origin of species. Conflicts associated with misregulation of transposable elements in hybrids expectedly resulted in their activation and genome-wide changes that may be key to species boundaries. Repetitive genomes of wild wheats have diverged under differential dynamics of specific long terminal repeat retrotransposons (LTR-RTs), offering unparalleled opportunities to address the underpinnings of plant genome reorganization and speciation under the influence of selfish sequences.

The investigation of a natural hybrid zones between Aegilops geniculata and Aegilops triuncialis revealed that conflicting LTR-RTs presented asymmetrical introgression and specific reorganization among natural hybrids. Specific reorganization of those LTR-RTs among viable hybrids indicated that they may represent genome-wide incompatibilities shaping species boundaries zones.

Moreover, experimental reciprocal F1 hybrids between those species assessed restructuring and epigenetic repatterning in relation to the strength of reproductive isolation. Asymmetrical reorganization of LTR-RT families predicted to cause conflicting interactions matched differential survival of F1 hybrids. In particular, non-random sequence losses and methylation appeared coherent with the necessary repression of incompatible loci in sustaining hybrid viability, confirming and LTR-RTs may foster species integrity in face of gene flow.

## Transposable elements in animals of varying age and reproductive mode (52785)

Jens Bast, Ina Schaefer, Mark Maraun, Stefan Scheu, Ken Kraaijeveld.

*University of Lausanne, Department of Ecology and Evolution, Lausanne, Switzerland;*
*Georg-August-University Goettingen, J.F. Blumenbach Institute, Goettingen, Germany;*
*University of Amsterdam, Department of Animal Ecology, Amsterdam, The Netherlands.*
The prevalence of sexual reproduction among eukaryotes is a central question in evolutionary biology. Genetic models predict the early demise of parthenogenetic lineages through accumulation of transposable elements (TEs), due to reduced efficiency of purifying selection. However, asexual reproduction should align the interests of hosts and TEs, leading to a decrease in TE abundance and activity given sufficient time. This predicts accumulation of deleterious TEs in newly arisen asexual lineages but a lower TE load in asexuals that have persisted for prolonged periods as compared to sexuals. To investigate this hypothesis, we analyzed the TE content of three animal groups of varying phylogenetic age using whole genome data. Overall, there was no evidence for TE accumulation in independent lineages that recently switched to asexuality (Leptopilina and Daphnia). However, certain TE families (Gypsy) were more abundant in these asexuals. By contrast, species under prolonged asexuality (oribatid mites), harbored only few and mostly inactive TEs. This suggests, that early extinction of asexual populations is unlikely to be caused by an overall expansion of TE copies in their genomes, but potentially by certain TE types if not contained. Furthermore, TEs might be cleared from asexual species over time in at least some cases.

# Major QTL of a morphological lock-and-key mechanism in Drosophila santomea and Drosophila yakuba (51579)

**Alexandre E. PELUFFO**, Isabelle NUEZ, Rosina SAVISAAR, Vincent DEBAT, David L. STERN, Virginie ORGOGOZO.

Institut Jacques Monod, CNRS-Université Paris Diderot/Sorbonne Paris Cité, Paris, France; ISySEB Département Systématique et Evolution, MNHN, Paris, France; Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, USA.

The recently discovered D. santomea is endemic to the African island of Saô Tomé where it hybridizes with its closest relative species D. yakuba (0.5-1 million year divergence). One of the prezygotic barriers limiting gene flow between these two species is a lock-and-key mechanism acting at the level of genitalia morphology. In D. yakuba, male spiny ventral branches contact female protective pockets during copulation. In D. santomea the ventral branches have a rounded shape and female pockets are absent. Interspecific mating induces female wounding or sperm leakage. The difference in ventral branch shape provides a unique opportunity to tackle the question of 1) rapid morphological evolution in genitalia and 2) the genetic basis of adaptive morphological evolution.

To identify the loci involved in this key evolutionary change in male ventral branches, we performed a QTL mapping with 400 progeny individuals from an interspecific backcross. Individuals were phenotyped using geometric morphometric methods and genotyped at a fine scale genome-wide resolution using Multiplexed Shotgun Genotyping. We identify one major QTL with a very strong signal in a small autosomal region and are now performing introgression mapping to identify specific genes.
# BayeScEnv: A new Fst-based method to uncover local adaptation using environmental variables (51617)

**Pierre de Villemereuil**, Oscar E. Gaggiotti.

*Laboratory of Alpine Ecology, Université Joseph Fourier; Scottish Oceans Institute, University of St Andrews.*

Genome scan methods, which aim at detecting selection using dense genotypic markers, can be separated into two main families: (i) Fst-based methods that detect outlier loci based on genetic differentiation and, (ii) Environmental methods that detect significant correlations between environmental factors and allele frequencies.

Because no method of the first family takes advantage of environmental information, we decided to develop a new method that combine two existing Bayesian approaches, BayeScan (Foll & Gaggiotti, 2008) and GESTE (Foll & Gaggiotti 2006). This method aims at revealing signatures of local adaptation by explaining locus-specific patterns of genetic differentiation in terms of environmental ``differentiation''. Just as BayeScan, it is based on the F-model (Gaggiotti & Foll, 2010), but unlike it, BayeScEnv explicitly models local adaptation in order to distinguish it from spurious locus-specific effects (high mutation rate, background selection).

A simulation study shows that BayeScEnv has a lower False Discovery Rate than BayeScan, although it has a lower power. Overall, it represents a better compromise between false positives and power than its predecessor. We illustrate the use of this new method with an application to a Human Single Nucleotide Polymorphism (SNP) dataset. The comparative interest of each method in then discussed in the conclusion.

# Genotyping museum samples from extinct vs extant populations to identify genes affecting adaptation (51647)

**Toby Fountain**, Marko Nieminen, Jukka Sirén, Swee Wong Chong, Ilkka Hanski.

*University of Helsinki.*

The application of Next Generation Sequencing to ecological model species facilitates the study of adaptation in natural populations. The ecological dynamics of the Glanville fritillary metapopulation in the Åland islands in SW Finland have been studied for over 20 years, producing a unique understanding of these dynamics across a large heterogeneous area. Recently, the full genome has been published along with two experimental RNAseq datasets. We selected 272 SNPs within genes indicated as under likely selection for increased or reduced flight capacity in RNAseq experiments, along with putatively neutral markers, and genotyped 10,000 individuals from three regions in Åland. We also genotyped 119 individuals from museum collections sampled between 50 and 150 years ago from extinct and extant populations across the Baltic. We used the F-model to calculate population and locus-specific drift values for the museum samples in comparison with a contemporary reference population. This approach has strengthened evidence that a subset of loci previously identified as candidate markers may be under selection in natural populations, with the majority in genes
related to flight and host plant use. We discuss the significance of incorporating ecological,
demographic and phenotypic data with a candidate gene approach to investigate loci under
selection.

Validating SNPs underlying local adaptation in lodgepole pine (51700)

Kimberly J. Gilbert, Nicholas K. Ukrainetz, Sally N. Aitken, Michael C. Whitlock.

University of British Columbia; BC Ministry of Forests, Land and Natural Resource
Operations.

Detecting the loci that underlie local adaptation is a difficult task, but one which is highly
sought after. Methods for identifying such loci include environment-allele correlations, FST
outlier tests, and genome-wide association studies (GWAS). However, these methods are
subject to false positives from neutral processes that may leave behind signatures of selection
on the landscape. In this study, I aim to validate the identification of selected SNP loci
underlying adaptation to climate conditions in the lodgepole pine, a common timber tree in
British Columbia. A larger study at the University of British Columbia has identified such
selective SNPs from the aforementioned methods, using samples collected across the
provinces of BC and Alberta and grown as seedlings in varying induced climates under
growth chamber conditions. My study has sampled natural-growing, mature (>40 year-old)
trees from the long-term, large-scale Illingworth provenance trials. I use these samples to
assess whether lifelong selection on individuals leads to the same selective SNPs being
identified in populations adapted to specific climate conditions, therefore serving to validate
the selection of loci underlying local adaptation.

Boosting inference power by gathering time-serial data: an example from
influenza virus (51753)

Claudia Bank, Jeffrey Jensen.

School of Life Sciences, EPFL; Swiss Institute of Bioinformatics.

The recent genomics revolution has provided us with novel means to study the processes that drive evolution at the molecular level. High-throughput genome sequencing enables us to survey genetic variation over multiple generations at modest costs, and new technical developments allow for the extraction and sequencing of DNA from ancient specimens. As compared with genome scans from a single time point, genomic time-serial data obtained from natural populations or generated by experimental-evolution approaches dramatically increase the power to investigate the mechanisms that drive evolution. Here, we use time-sampled whole-genome SNP data from a mutation-accumulation experiment in influenza H1N1 under various environmental conditions (represented by different antiviral drug
treatments) to identify loci involved in adaptation, and discuss their potential functional role
in the evolution of drug resistance. We further point out the limits and challenges of current
approaches to time-serial selection inference, and lay out a roadmap for future developments.

Females with long legs: signatures of selection in the genome of the South African bee genus Rediviva (51783)

**Belinda Kahnt**, Antonella Soro, Michael Kuhlmann, Robert J. Paxton.

Martin-Luther-University Halle; The Natural History Museum, London.

The great phytodiversity of the South African Succulent Karoo is thought to be due to the
close interaction and reciprocal adaptation of plants and their pollinators. Rediviva bees and
their Diascia host plants represent a particularly fascinating example of such a co-
evolutionary relationship. In order to collect oil from the long spurs of its host plant, Rediviva
females have evolved a unique adaptation: elongated forelegs, which show not only inter- but
also intraspecific variation and are significantly correlated with spur length of Diascia hosts.
We aim to understand the genetic underpinning of leg length in Rediviva. We RAD
(Restriction-site-Associated DNA) sequenced 60 individuals from two adjacent populations of
Rediviva longimanus, significantly differing in leg length, and use these data to: i)
characterise SNPs ii) identify regions under selection using an FST-outlier approach; iii)
sequence FST-outliers found in coding regions of R. longimanus in the sympatric R.
intermixta and R. macgregori, species with shorter forelegs, and iv) test for signatures of
selection by analysis of the KA/KS ratio. Results of our studies not only inform processes of
adaptation and speciation in co-evolving pollinator-plant systems but are also of great
relevance for the conservation management of both endemic genera.

QTL mapping of stress related traits in the model brown alga Ectocarpus
siliculosus (51789)

**Komlan Avia**, Fiona Lerck, Stephane Mauger, Susana Coelho, Pierre Boudry, Myriam Valero, Mark Cock.

Algal Genetics Group, LBI2M UMR 8227 CNRS-UPMC, Station Biologique Roscoff, France;
Evolutionary Biology and Ecology of Algae, UMI 3614, Station Biologique Roscoff, France;
Unité Physiologie Fonctionnelle des Organismes Marins, UMR 6539 LEMAR, IFREMER
Plouzane, France.

Brown algae are complex photosynthetic organisms with a very different evolutionary history to green plants. They are dominant species in rocky coastal ecosystems. They are economically important as food products, animal feed, fertilizer, source of polysaccharides or other important extracts, or even biofuel resources. Despite their importance, many aspects of
these organisms are still poorly understood. The filamentous brown alga Ectocarpus
siliculosus has been proposed as a general model for the brown algae and its genome has been
sequenced.

As sessile organisms, brown algae require high levels of tolerance to various abiotic stressors (osmotic pressure, temperature, salinity, light) and previous studies showed that an important proportion of the expressed genes are regulated in response to hyposaline, hypersaline or oxidative stresses.

Using double digest RAD sequencing method, a denser genetic map has been constructed and QTL for stress-related primary and secondary phenotypes have been mapped. These first results of QTL mapping in Ectocarpales are discussed in the light of the peculiar as well as common characteristics of these species relative to other algae and land plants.

Poster session B - MAX 412

Distribution of chromosome identical-by-descent block length as an
integrating multilocus approach in population genetics (52162)

Mathieu Tiret, Frédéric Hospital.

INRA Jouy en Josas.

In population genetics, incorporating NGS data requires to consider multiple loci at once, and hence take account of multiple levels of likeage disequilibrium. Here we address this from the identity by descent (IBD) relationship: two chromosome tracts are said to be IBD if they are copies of a same ancestral chromosome without having undergone any mutation nor recombination. Because of recombinations, all the genome cannot remain IBD for the whole population, and so genomes split into blocks of IBD zones and non-IBD zones. We study the length distribution of such IBD blocks over time in a neutral context.

Using the theory of junctions (Fisher, 1954), and a Wright-Fisher model with recombination, we derived an approximation of the average IBD block length in a population, which depends only on heterozygosity, population size and time. Under this approximation, there is a transient phase during which the average length is constant. Since the duration of this phase increases with population size, we conclude that average IBD block length should remain constant in large populations.

Poster session B - MAX 412

Identification of Arctic population of Mytilus mussels based on SNP markers
(52228)

Małgorzata Zbawicka, Lis Bach, Jakob Strand, Roman Wenne.

Institute of Oceanology; Aarhus University.
Mussels Mytilus are widespread in northern and southern hemispheres and are known to inhabit subarctic and arctic regions, where must conform to extremely harsh environmental conditions. The Mytilus species are very important component of marine coastal ecosystems. Information of genetic biodiversity have importance for biogeography, and environmental monitoring studies related to global climate changes.

Molecular markers based on single nucleotide polymorphisms (SNPs) were used for study the population structure and identifying the geographical origin of the Arctic mussels.

Genotyping of SNPs was performed using the Sequenom MassARRAY iPLEX platform.

Sixty six polymorphic SNPs were used to genotype Mytilus spp. samples, consisting of 700 individuals, collected from Greenland, Iceland, and Spitsbergen. Reference samples from North America and Europe were used. The highest heterozygosity was observed in the populations from a Greenlandic fjord, at Maarmorilik, and in sample from Spitsbergen, and the lowest in Savissivik in Northwest Greenland. Correspondence Analysis, Structure and fixation index values based on SNPs very clearly show diversity among and within the studied populations. The outlier detection was carried on to identify candidate loci that might be under selection. The obtained results indicate the high potential of the SNPs markers in the study of population structure and admixture level of mussels of the genus Mytilus in the Arctic

Poster session B - MAX 412

# Eco-evolutionary dynamics in response to seasonal adaptation in Drosophila (52253)

**Subhash Rajpurohit**, Alan Bergland, Martin Turcotte, Jonathan Levine, Dmitri Petrov, Paul Schmidt.

University of Pennsylvania; Stanford University; ETH Zurich.

In temperate populations of D. melanogaster, the rapid and cyclical adaptation to seasonality is driven by multiple genes and phenotypes. Using an experimental orchard with insect enclosures, we generated large outbred populations from fully sequenced, inbred lines and manipulated the rate of evolution in response to changing seasonal parameters. We examined how the adaptive response to seasonality over the agricultural growing season determines fundamental aspects of population ecology and, in turn, how changing ecological dynamics affect the subsequent evolutionary response. Our data demonstrate a predictable genomic and phenotypic adaptive response to seasonality, and that this adaptive response results in a faster rate of population growth and a higher carrying capacity. The differential density between treatments over time was associated with evolutionary change in several traits that affect fitness in a density-dependent fashion. These experiments suggest a fundamental interplay between ecological and evolutionary dynamics in natural populations that inhabit seasonal environments.

Poster session B - MAX 412
# The power to detect selection from gene frequencies variation in 10 generations (52384)

**Jean-Noël Hubert**, Frédéric Hospital.

*INRA Jouy en Josas.*

Available strategies to identify targets of selection in the genome include population genomics and especially bottom-up analyses seeking footprints of selection. Various methods developed through this scope allowed detecting even small cumulative effects of selection over large timescales. By contrast, looking for selection in small populations undergoing a strong directional selection during only a few generations, as it may be the case in selection experiments or in response to rapidly changing environments, received a limited attention. We propose to address this issue by coupling a diallelic Wright-Fisher model to a maximum-likelihood approach. Individual-based simulations, performed under this approach with 10-generation long scenarios, indicated that detecting selected SNPs by following the variation of allele frequencies over a very short period of strong directional selection is feasible. Importantly, the initial situation at each considered SNP in terms of allele frequency and linkage disequilibrium, in addition to the selection intensity, was shown crucial to get enough power of detection. Our maximum-likelihood estimation seems adapted for inferring selection due to rapid adaptation, in particular those caused in the course of selection experiments.

Poster session B - MAX 412

# Hybrid zones as natural laboratories to study adaptation in host-parasite systems: the Murine cytomegalovirus in the European house mouse hybrid zone (52531)

**Joelle Gouy de Bellocq**, Stuart J.E. Baird, Jaroslav Pialek.

*Institute of Vertebrate Biology, ASCR.*

When hosts and their parasites co-diverge during isolation, their secondary contact creates a natural laboratory for investigating loci underlying adaptation in host-parasite systems. We sampled mice across a 145-km transect in the Bavaria-Bohemia region of the hybrid zone between Mus musculus domesticus and Mus musculus musculus to investigate the occurrence and the genetic structure of a common herpesvirus of mice, the Murine cytomegalovirus (MCMV). We screened 319 lung samples collected from 97 localities by nested-PCR. 133 were positive, and for these we sequenced 6 genes distributed across the genome and analysed their genetic structure. The two mouse taxa carry different strains of MCMV. Four genes located centrally in the MCMV genome and involved in the viral life cycle were structured in close accordance with the host genetics. In contrast, genes located at both extremities of the genome and involved in the subversion of the host immunity have recombined and introgressed. This result lets us glimpse the potential of parasite genomic studies in host hybrid zones for identifying potential candidate genes underlying adaptation. Sequencing of a sample of MCMV genomes will provide a more detailed picture of the introgressive viral genes.
# Local adaptation in osmoregulatory physiology in sticklebacks (52585)

Jacquelin De Faveri, Mehedi Hasan, Satu Kuure, Sanna Lehtonen, Surjya Dash, Scott McCairns.

University of Helsinki.

Organisms living in high and low salinity environments face opposing physiological demands in order to survive the challenges posed by environmental salinity. Earlier studies of three-spined stickleback (Gasterosteus aculeatus) have suggested that populations residing in low salinity regions of the Baltic Sea have become locally adapted to their native salinity conditions. However, the physiological and functional genetic basis of this adaptation has remained unstudied. For example, signatures of selection have been detected in several genes related to osmoregulation, yet their functional role has not been validated. In this study, we integrate candidate gene expression and comparative kidney cell morphology to explore the physiological underpinnings of adaptation to low salinity environments in Baltic three-spined stickleback. A factorial common garden experiment revealed a high degree of plasticity in kidney cell morphology and candidate gene expression in the population residing in high salinity regions of the Baltic Sea. In contrast, the native low-salinity population showed little changes in response to differences in environmental salinity, suggesting canalization of key osmoregulatory traits.

# Genome wide approach to detect positive selection on the plant pathogen fungal genus Colletotrichum (52610)

Ana Vieira, Diogo N. Silva, Octavio S. Paulo, Dora Batista.

COBIG2, CE3C, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal; CIFC/Biotrop/Instituto de Investigação Científica Tropical, Oeiras, Portugal.

Natural selection leaves imprints on DNA, offering the opportunity to identify functionally important regions of the genome. Currently, with the rapid accumulation of genome sequences and the development of powerful statistical methods to detect signatures of adaptation, it is possible to pinpoint genomic regions under selection. Recent studies have shown the importance of looking for genes under positive selection in pathogens, since this allows to better understand the co-evolution dynamics of host-pathogen interactions and aid in the pursuit of effective strategies to control diseases. The fungi Colletotrichum spp. are listed in the "Top 10" of the most economically devastating groups of plant pathogens, causing severe diseases in a vast range of crops throughout the world, and have been associated with several cases of emergent plant diseases in new hosts. In this study, we used a genome-wide approach to screen for positive selection across as many orthologous as possible from the six full genome sequenced species of the Colletotrichum genus, adapted to different hosts and
representing different lifestyles (C. graminicola; C. higginsianum; C. orbiculare; C. acutatum var. fioriniae, C. sublineola and C. gloeosporioides). New candidate genes are being identified and functions putatively involved in different adaptive processes will be discussed. Funded by FCT grant SFRH/BD/89397/2012.

# Mapping of quantitative trait loci (QTL) for fitness-related traits in the house sparrow (52630)

**Henrik Jensen**, Ingerid Hagen, Anna Billing, Henrik Pärn, Bernt Rønning, Thor Harald Ringsby, Bernt-Erik Sæther, Sigbjørn Lien, Arild Husby.

*Norwegian University of Science and Technology; Norwegian University of Life Sciences; University of Helsinki.*

A major challenge in evolutionary biology is to understand the genetic processes and mechanisms that enable populations to adapt to environmental changes. The recent revolution in high-throughput molecular methods has made development of large numbers of molecular markers, genetic maps, and even whole-genome sequencing affordable also in non-model species. This allows study of the genetic architecture of quantitative traits by use of quantitative trait locus (QTL) mapping in natural populations, which will provide invaluable information to improve our understanding of the genetics of adaptation. Here, we used genomic resources recently developed for the house sparrow (Passer domesticus) to genotype more than 6000 Single Nucleotide Polymorphisms (SNPs) with known position, in ca. 2000 individuals from long-term studies of a set of natural populations in northern Norway. QTL mapping of fitness-related morphological traits was carried out by Genome Wide Association Studies (GWAS) and identified QTL for some of the morphological traits. Variation in the allele frequencies of SNPs within these QTL was then examined across generations and populations. By relating these patterns to the observed spatio-temporal phenotypic variation as well as the strength and direction of phenotypic selection we are starting to understand some genetic mechanisms for adaptation in these populations.

# Identifying the Loci of Selection in a 30-Year Long Selection Experiment for Longevity in Drosophila melanogaster (52650)

**Kathrin I. Garschall**, Daniel K. Fabian, Martin Kapun, Robert Arking, Christian Schlötterer, Thomas Flatt.

*Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland; Institute of Population Genetics, University of Veterinary Medicine Vienna, Vienna, Austria; Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Department of Biological Sciences, Wayne State University, Detroit, USA.*
To study the mechanistic basis of the evolution of longevity, we have recently performed whole-genome sequencing of experimental replicate populations of Drosophila melanogaster that have been undergoing selection for postponed senescence for over 30 years. Based on our analysis of highly differentiated single nucleotide polymorphisms (SNPs) between longlived selection and non-selected control lines, we have identified numerous candidate genes as potential targets of selection for increased lifespan. For example, a particularly interesting set of genes, strongly genetically differentiated between selection and control lines, are involved in innate immunity. In support of their functional relevance, we find that the evolved lines outperform controls in pathogen infection assays, and preliminary qPCR data suggest that selection lines differ substantially from the controls in the expression of several immune genes. Here we aim to complement and extend these findings by applying transcriptomic (RNA-seq) analyses to this long-term selection experiment. Comparing these gene expression data to our DNA sequence data allows to substantially refine our list of candidate loci for further functional experimental testing.

# Seed dormancy contributes strongly to local adaption in Arabidopsis thaliana (52672)

Froukje M. Postma, Jon Ågren.

Uppsala University.

Seed dormancy is a key life-history trait in plants, but its role in local adaptation remains poorly known. We examined the genetic basis and adaptive significance of seed dormancy in a reciprocal transplant experiment using 220 Recombinant Inbred Lines (RILs) derived from a cross between two populations of Arabidopsis thaliana from the northern and southern limits of its native range (Italy and Sweden). We mapped QTL for seed dormancy and fitness (number of fruits produced per seed planted) using seeds matured at the respective field site and planted at the time of seed dispersal, in one year in Italy and in three years in Sweden. The local genotype had higher fitness than had the non-local genotype at both sites in all years. We found strong divergent selection on seed dormancy between the two sites, with temporal variation in the strength of selection in Sweden. We detected 6 dormancy QTL of which 4 overlapped with fitness QTL. The dormancy QTL with the strongest effect was significant at both field sites and colocated with the dormancy gene DOG1. The results demonstrate that genetically based differences in seed dormancy play an important role in adaptive differentiation among natural populations of A. thaliana.

# Dertermination of the selection process acting on the PGM in Alevinella Pompejana (52673)

BIOY Alexis, LE PORT Anne Sophie, MARY Jean, JOLLIVET Didier.
The Pompeii worm occurs exclusively on hydrothermal-vent chimneys along the East Pacific Rise (EPR). This environment is considered as one of the most extreme and variable in temperature. Previous works on the phosphoglucomutase revealed that diversifying selection acts on the frequencies of isoforms 78, 90 and 100 between thermal habitats at small spatial scales. Both protein stability and thermal optimum of enzyme activity were clearly different between isoforms. Allozymes also displayed a clinal distribution from North to South with an abrupt replacement of isoform 100 by isoform 78. In the present study, alleles encoding these isoforms were completely sequenced from northern and southern individuals. The distribution of highly divergent alleles without recombination on both sides of the EPR are likely the result of balancing selection combined with spatial isolation. Only two non-synonymous mutations (EQ) located in the exon 3 explain the polymorphism of charge. Directional mutagenesis allowed us to mutate allele 100 into the two other alleles and to overexpress them to explore the additive effect of the mutations over the biochemical properties of the enzyme in the face of temperature. Results are coherent with those obtained on native proteins and showed the direct effect of mutations on the protein thermostability.

# Lipocalin Gene Expression Divergence in Drosophila melanogaster and Drosophila simulans (52696)

Banu Sebnem Onder, Nazli Ayhan, Pinar Güler.

Hacettepe University; Aix Marseille University.

Environmental stressors are among the strongest forces of natural selection. When organisms encounter with an environmental stress, the characters of organisms are shaped by evolutionary adaptive mechanisms to buffer these factors. Studies with Lipocalin genes have shown that stress responsive signal pathways are important for regulation of the lipocalin genes expression and metabolic adaptation of the organism to environmental challenges. Besides, lipocalin gene family is evolutionarily conserved from flies to vertabrates. Here, we present analyses of expression divergence in adults of two recently diverged species of Drosophila. Depending on the aging and dietary stress, single-gene expression of lipocalin genes NLaz, GLaz and Karl was quantified. We found different gene expression responses between two species in different age intervals and under dietary stress. D. melanogaster showed up-regulation with age in all lipocalins, whereas D. simulans showed different age-related expression patterns. Further, we found that malnutrition could affected lipocalin expression patterns reveal the differences between species. Results of this experiment showed that the present lipocalin genes might be differ within sibling species in terms of function or regulation.
# Efficient detection of novel nuclear markers for Brassicaceae by transcriptome sequencing (52715)

**Reinhold Stockenhuber**, Stefan Zoller, Rie Shimizu-Inatsugi, Felix Gugerli, Kentaro K. Shimizu, Alex Widmer, Martin C. Fischer.

*University of Zurich, Institute of Evolutionary Biology and Environmental Studies; ETH Zürich, Genetic Diversity Center; WSL Swiss Federal Research Institute; ETH Zürich, Institute of Integrative Biology.*

The lack of DNA sequence information for most non-model organisms impairs the design of primers that are universally applicable for the study of molecular polymorphisms in nuclear markers. Next-generation sequencing (NGS) techniques provide a powerful approach to overcome this limitation. We present a flexible and inexpensive method to identify large numbers of nuclear primer pairs that amplify in most Brassicaceae species. We first obtained and mapped NGS transcriptome sequencing reads from two diverged Brassicaceae members, Cardamine hirsuta and Arabis alpina, onto the Arabidopsis thaliana reference genome, and then identified short conserved sequence motifs bioinformatically. From these, primers were developed and tested successfully on 30 Brassicaceae taxa. Sequence analysis and phylogenetic reconstruction with a subset of these markers on different levels of phylogenetic divergence in the mustard family were compared with previous results and corroborate the usefulness of our newly developed primer pairs, e.g., for phylogenetic analyses or population genetic studies. We identified 2,334 universally applicably primer pairs, targeting 1,164 genes, which provide a significant and readily usable genomic resource that will help addressing novel questions in the Brassicaceae family.

Poster session B - MAX 412

# Local adaptation at the transcriptomic level in European populations of Daphnia (52811)

**Mathilde Cordellier**, Suda Ravindran, Ann-Kathrin Huylmans, Alberto Lopez, Klaus Schwenk, John Parsch.

*Universität Hamburg; Ludwig-Maximilians-Universität München; Westfälische Wilhelms-Universität Münster; Universität Koblenz-Landau.*

Simultaneously phenotype and genotype, gene expression profiles are heritable, thus providing a substrate for evolution. In species with little or no gene flow between populations such as permanent Daphnia populations, local adaptation can lead to distinctive gene expression profiles within a single species. Selection drivers as diverse as parasitism, predation and heavy metal pollution were already shown to cause rapid genetic shifts in Daphnia.

In this study, we inferred the intra-specific variation at the transcriptome level in Daphnia galeata. A large scale RNAseq experiment was conducted on 24 clonally propagated genotypes from four European lakes. In total, 72 libraries were sequenced and long reads generated for assembly purposes. The de novo assembly was made using the EvidentialGene pipeline and used as a reference for the differential expression analysis. Candidate genes
exhibiting differential expression patterns between populations were relatively few, partly due
to the high variation within populations. Expression levels of these candidate genes will be
correlated with fitness measurements and sequence variation, in order to establish a link
between phenotype and genotype. The outcome of this study will allow us to understand the
genetic background of rapid adaptation to environmental changes in a key species of aquatic
ecosystems.

Genotype and phenotype in a changing ocean: can standing genetic variation
in stress responses rescue mussel populations from the negative impacts of
climate change? (52826)

Sarah E Kingston, Jenna Watling, Benjamin Eisenberg, David Carlon.

Bowdoin College.

As physical and chemical features of the ocean change in response to the changing climate, marine calcifiers face the biochemical and physiological challenge of maintaining calcium carbonate shell structure in a more acidic environment. A key component to understanding organismal response to this multifactorial stressor is linking underlying genetic variation to phenotypic variation in stress response. We take advantage of the genomic gradient across the blue mussel hybrid zone (Mytilus edulis and Mytilus trossulus) in the Gulf of Maine to link genetic variation with variance in calcification rates in response to lower pH, higher temperatures, and reduced food availability. Intertidal blue mussels were collected from midcoast Maine up to Cobscook Bay and subjected to a 14-day exposure in a laboratory common garden treatment of climate stress (20°C, pH 7.8, and low food availability). The control treatment simulated ambient Harpswell Sound summer conditions (17°C, pH 8.1, and high food availability). Interestingly, the climate stress treatment rendered significantly greater variation in calcification rates (change in buoyant weight) than the control treatment, while the means did not vary significantly. The calcification rate phenotypes were then linked to underlying genomic variation through a next generation sequencing-based SNP assay and genome-wide association survey.

Phylogenomics provides insights on the adaptive evolution of rust fungi
(52957)

**Diogo N. Silva**, Sebastien Duplessis, Pedro Talhinhas, Helena Azinheira, Octávio S. Paulo, Dora Batista.

Computational Biology and Population Genomics Group, Science Faculty, University of
Lisbon; Centro de Investigação das Ferrugens do Cafeeiro/BioTrop, IICT; Institut National
de la Recherche Agronomique, UMR 1136 INRA/Université de Lorraine; Université de
Lorraine, UMR 1136, INRA/Université de Lorraine.
In this work, we employed a phylogenomics approach focused on single-copy genes shared by 38 Basidiomycota species to search for signatures of natural selection during the evolutionary origin of the rust fungi (Pucciniales). We identified 1006 orthologs that were screened for positive selection acting specifically at the basal branch of the rust fungi. In total, 1103 positively selected codon sites were uncovered across 185 genes (18%), which is a surprisingly high proportion given the fact that these genes are conserved across the Basidiomycota. To further assess the adaptive impact of the positively selected sites on the evolution of rust fungi, sites were sorted depending on whether they remained unchanged or continued diverging throughout the diversification of rust fungi. While the majority of the positively selected sites (78%) remained unchanged and, therefore, represent prime candidates to help us understand the early divergence of rust fungi, the remaining 22% of the sites continued to diverge and may represent candidates contributing for the origin of rusts and species-specific traits. We will discuss the functional categories enriched for each type of the positively selected genes as well as the usefulness and impact of genome-wide screens of positive selection. Funded by FCT PTDC/AGR-GPL/119943/2010 and SFRH/BD/86736/2012.

# Analysis of allele-specific expression in a putative pathogenesis-related gene of coffee leaf rust (52964)

**Inês S. Modesto**, Andreia Luoreiro, Renata Martins, Ana Paula Pereira, Vítor Várzea, Octávio S. Paulo, Dora Batista, Célia Miguel.

iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; CIFC-Biotrop, IICT, Quinta do Marquês, 2784-505 Oeiras, Portugal; CoBiG², Ce3C, FCUL, Campo Grande, 1749-016 Lisboa, Portugal; ITQB-UNL, Av. da República, 2780-157 Oeiras, Portugal.

Hemileia vastatrix is a rust fungus responsible for one of the main devastating diseases of Arabica coffee. Durable coffee resistance has been hampered by the high capacity of H. vastatrix to adapt, driven by the dynamic of host-pathogen co-evolution. In this scenario, it is pressing to understand the mechanisms underlying adaptation in H. vastatrix populations. In a previous study, population genetic variation was analyzed for a set of pathogenesis-related candidate genes activated during the early stages of H. vastatrix infection as identified from a 454-transcriptomic dataset. For one such genes, a pattern of very divergent alleles particularly related with coffee hosts was found revealing a clear structuring of genetic variation with a probable adaptive significance. Allele-specific expression has been detected as common and widely distributed along several taxa, leading to phenotypic variation, and underlying adaptation. In a first attempt to elucidate its functional activity, we investigated the candidate gene expression profile in different rust isolates bearing contrasting allelic compositions, along the different stages of the infection process, using real-time PCR to discriminate putative allelic asymmetric expression. The differential expression profiles obtained will be discussed concerning putative causal relations between allelic variants and pathotypes, and their possible adaptive significance.
Finding the genes which make great tits innovators (52967)

**Veronika Laine**, Toni Gossmann, Kees van Oers, Kyle Schachtschneider, Ole Madsen, Kai Zeng, Jon Slate, Marcel Visser, Martien Groenen.

*Netherlands Institute of Ecology (NIOO-KNAW); University of Sheffield; Wageningen University.*

For more than 50 years the great tit (Parus major) has been a prime model species for ecological, behavioural and evolutionary studies. Studies of learning and cognition in great tits suggest that this species displays an unusual propensity for behavioural plasticity and social learning in response to environmental challenges. Here we sequenced to high coverage, de novo assembled and annotated the genome of the great tit. Furthermore, we sequenced the methylome of two tissues, RNA of eight tissues and whole genomes of 29 additional individuals to identify genomic regions under positive selection in this species. These regions show an increased level of CpG methylation, decreased non-CpG methylation, and an overrepresentation of genes related to learning and cognition, traits which seem to be important in recent adaptive evolution of great tits. These observed patterns raise interesting questions regarding neuronal epigenetic regulation and the potential role of methylation in learning, memory and experience-induced plasticity.

Comparative phylogenetic analysis of sex allocation evolution in the
hermaphroditic flatworm genus Macrostomum. (51713)

Jeremias Brand, Toon Janssen, Dita B. Vizoso, Lukas Schärer.

*Zoological Institute, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland;*
*Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghe.*

In simultaneous hermaphrodites sex allocation is the decision about relative investment into male versus female reproduction. Sex allocation is strongly influenced by the intensity of sperm competition, which can vary drastically between species. In species with traumatic insemination (sperm injection through the body wall with an intromittent organ) sperm competition is likely to follow a fair-raffle model and may therefore be high as injected sperm are swimming through the tissue in the search of eggs. Conversely, in species with copulation (insertion of an intromittent organ into a female sperm receiving structure) sperm are more likely to compete with related sperm due to the possibility for sequential sperm displacement and cryptic female choice. Here we present results from work combining photomicrographic documentation of field collected worms and a molecular phylogeny of 50 species of Macrostomum. We estimated relative gonad size, since it has previously been shown to be a useful proxy for sex allocation in Macrostomum, and evaluated its distribution across the phylogeny to test whether sex allocation is free to evolve or phylogenetically constrained in this genus. Furthermore, we measured qualitative and quantitative traits of male and female
sexual organs to map their phylogenetic distribution and investigate whether combinations of
these traits are phylogenetically correlated to sex allocation.

Do females produce more sons when mating with more attractive males?
(51757)

Isobel Booksmythe, Brian Mautz, Jacqueline Davis, Shinichi Nakagawa, Michael Jennions.

University of Zurich; Uppsala University; University of Cambridge; University of Otago;
Australian National University.

Do females produce more sons when mating with more attractive males? Early support for this prediction has become less clear-cut over time. Rapidly accumulating empirical studies are broadening the range of taxa, mating systems, attractive traits and moderating factors included in tests of the hypothesis. Additionally, theoretical advances have questioned whether sex allocation in response to mate attractiveness should be either expected or empirically detectable. We used meta-analysis for a quantitative review of the empirical literature on this topic. The mean effect size was very small, but statistically significant in the predicted direction. It was not, however, robust to correction for an apparent publication bias towards significantly positive results. We also examined the strength of the relationship using different indices of male attractiveness. Of these, ornamentation and body size predicted the proportion of sons produced, but again these effects were very small. Our study provides weak support for a relationship between male attractiveness and the offspring sex ratio, but highlights the need for more powerful empirical tests. Ultimately, we need more direct experimental tests of whether females produce more sons when mated to more attractive males, that also provide evidence this occurs because sons have higher mean fitness than daughters.

Divorce and infidelity are associated with skewed adult sex ratios in birds
(51949)

Tamas Szekely, Andras Liker, Robert Freckleton.

University of Bath; University of Pannonia; University of Sheffield.

Adult sex ratio (ASR) is a fundamental concept in population demography, and recent theory suggests that ASR plays a central role in social behaviour, mating systems and parental care. Unbalanced ASRs are predicted to influence pair-bond and mating behaviour since the rarer sex in the population has more potential partners to mate with than the more common sex. Here we use phylogenetic comparative analyses to test whether ASR is related to three major aspects of mating behaviour: divorce, social polygamy and pair-bond infidelity. ASR is strongly correlated with long-term pair-bonds since divorce rate is higher in species with
female-biased sex ratio, indicating that mate change by pair members and/or breaking of pair-bonds by unmated individuals is more frequent when females outnumber males. Short-term pair-bonds are also associated with ASRs: males are more commonly polygamous when females outnumber males, and conversely, females are more polygamous when males outnumber females. Furthermore, infidelity increases with male-biased ASR in socially monogamy, suggesting that male coercion and/or female willingness to cheat the partner are facilitated by male-biased ASR. Our results provide the first comprehensive support for the proposition that ASR influences multiple aspects of pair-bonds and mating behaviour in wild populations.

## Socially sensitive gene expression analysis of seminal fluid proteins in a simultaneously hermaphroditic marine flatworm (51984)

**Bahar Patlar**, Steven Ramm.

*Bielefeld University.*

The ejaculate often contains many seminal fluid proteins that are transferred along with sperm during mating. Since it is known that these proteins function in diverse ways to maximize male reproductive success, often exerting strong effects on female reproductive physiology and behaviour, the study of SFPs has become a central concern of sexual conflict research. Considering that production of seminal fluid is costly, we expect individuals to strategically invest in SFP production according to the level of sperm competition. This study examines the impact of social environment on SFP production in the simultaneously hermaphroditic marine flatworm *Macrostomum lignano*. It is well known that individuals of *M. lignano* kept in larger social groups invest more in male reproductive traits than individuals in smaller social groups, presumably as a consequence of sperm competition and as predicted from sex allocation theory. Thus, we predict that the transcriptional activity of seminal fluid genes in worms will also differ between large versus small social group sizes. Moreover, by measuring seminal fluid gene expression in multiple inbred lines, we can assess genetic variation for expression plasticity of these genes, i.e. to test for genotype-environment interaction effects as a response to differing social environments.

## Maladaptive sex ratio manipulation in invasive *Artemia franciscana* (51999)

**Eva JP Lievens**, Gil Jorge Barros-Henriques, Yannis Michalakis, Thomas Lenormand.

*CEFE, CNRS Montpellier; MIVEGEC, CNRS Montpellier.*

Sex allocation theory is often hailed as the most successful area of evolutionary theory, and sex allocation traits are typically expected to respond quickly to changing selection pressures. Here, we demonstrate that this is not always true. We studied French populations of the sexual
brine shrimp Artemia franciscana, which invaded from the Americas in the 1970s (200-500 Artemia generations ago). Since then, A. franciscana has coexisted with a native parthenogenetic species, Artemia parthenogenetica. First, we report the regular occurrence of extremely male-biased sex ratios in natural populations of invasive A. franciscana, and we show that the extent of male-biasing is predicted by the proportion of A. parthenogenetica in the population. Second, we experimentally prove that both native-range and invasive-range A. franciscana overproduce sons when exposed to an excess of females, without distinguishing between conspecific and parthenogenetic females. We conclude that A. franciscana have an ancestral ability to plastically 'correct' skews in the population sex ratio, which has persisted unchanged in the invasive range despite being maladaptive in the presence of A. parthenogenetica. This study demonstrates that although sex allocation is a key life-history parameter with large effects on fitness, it is still subject to constraints that may dramatically slow adaptation.

# Testing for cytonuclear conflict over sex allocation in a simultaneously hermaphroditic flatworm (52043)

Nikolas Vellnow, Dita B. Vizoso, Lukas Schärer.

*University of Basel, Zoological Institute, Evolutionary Biology, Basel, Switzerland.*

Uniparental inheritance of cytoplasmic genes creates a potential for cytonuclear conflict over sex allocation. In particular, maternally inherited cytoplasmic genes in simultaneous hermaphrodites may be selected to reduce allocation towards male gametes. This can lead to the spread of cytoplasmic male sterility mutations and a consequent transition to gynodioecy, as found in many plant species. Curiously, gynodioecy seems to be rare or absent in animals. Here we provide a quantitative test for cytonuclear conflict over sex allocation in the simultaneously hermaphroditic flatworm Macrostomum lignano. We generated replicate crosses of 15 different pairs of inbred lines (2x15=30 independent lines), resulting in F1 offspring for each cross that had either of the two lines as the maternal parent. This design allows to compare the sex allocation of individuals with the same nuclear genome, but presumably different cytotypes. A preliminary analysis revealed significant effects of the nuclear genome, but no significant effects of cytotype on sex allocation, indicating absent or weak cytonuclear conflict. Analyses to evaluate the power of the experimental design are underway, but we hypothesize that the relatively small mitochondrial genome in animals compared to plants may be a reason why mutations that bias sex allocation arise less often in animals, leading to weaker cytonuclear conflict.

# Identifying the selective pressures underlying offspring sex-ratio adjustments to test a priori predictions: a case study (52048)
**Thomas Merkling**, Etienne Danchin, Jorg Welcker, A. J. Mark Hewison, Alexander S. Kitaysky, John R. Speakman, Scott A. Hatch, Pierrick Blanchard.

Université Toulouse 3 Paul Sabatier; CNRS; ENFA; UMR 5174 EDB; Australian National University; Research School of Biology; Norwegian Polar Institute; University of Alaska Fairbanks, Institute of Arctic Biology; INRA, UR035, CEFS; University of Aberdeen, Institute of Biological and Environmental Sciences; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Devpt Biolgoy; U.S. Geological Survey, Alaska Science Center; Institute for Seabird Research and Conservation.

Despite how crucial information on the benefits and costs of producing males or females is to correctly predict and interpret offspring sex-ratio results, it is currently lacking for vertebrates. However, one should ideally identify the underlying selective pressures before examining sex-ratio variation itself. Therefore, we did so in our study species, the black-legged Kittiwake (Rissa tridactyla), and examined the underlying assumptions of two plausible sex allocation models: the 'cost of reproduction hypothesis' and the 'Trivers-Willard hypothesis'. Using data from a long-term feeding experiment, we found stronger support for the former: rearing sons was energetically more costly for parents (higher energy expenditure and baseline corticosterone levels) than rearing daughters. Then, we made a priori predictions based on this difference in rearing costs and used a multiyear dataset to compare the explanatory power of six variables. Surprisingly, none of the 'classic' variables, such as food availability, were important predictors of offspring sex-ratio variation. Rather, pair-bond duration was the only important predictor, with a quadratic effect on sex-ratio that we interpreted in the light of the 'cost of reproduction hypothesis'. Future sex-ratio studies will certainly benefit from a more systematic investigation of the selective pressures occurring in a given species.

# The genetic architecture of sex allocation in a simultaneous hermaphrodite (52181)

**Steven A. Ramm**, Dita B. Vizoso, Lucas Marie-Orleach, Mathias Kölliker, Lukas Schärer.

Bielefeld University; University of Basel.

In simultaneous hermaphrodites, individuals can gain reproductive success through both male and female sex functions, and sex allocation (SA) describes the balance of investment into these two routes to fitness. Although it is clear that simultaneous hermaphroditism may have important consequences for the operation of sexual selection and sexual conflict, predicting the evolutionary response to the resulting selection pressures also requires knowledge of the underlying genetic architecture of sexual traits. We aimed to estimate relevant quantitative genetic parameters in a simultaneously hermaphroditic model system, the free-living flatworm Macrostomum lignano, using a three-generation breeding design involving over 1200 individuals. We measured a suite of male and female reproductive traits in two social environments favouring different SA, to estimate: 1) the heritabilities and within- and between-sex function genetic correlations for these traits, and 2) the magnitude of gene-by-environment interaction effects on SA. Parallel studies are aiming to identify the genomic basis of SA plasticity in this species, meaning we can now begin to piece together the
complex ways in which hermaphroditism might impact upon the expression and evolution of
sexual traits. We can thus test the generality of current conclusions about the genetics of
sexual traits based almost entirely on studying species with separate sexes.

# Sex role decisions of a simultaneous hermaphrodite: young and small snails choose to be male first (52225)

**Yumi Nakadera**, Elferra M. Swart, Jeroen J. P. Maas, Joris M. Koene.

*Animal Ecology, Ecological Sciences, VU University Amsterdam, the Netherlands;*
*Evolutionary Biology, Bielefeld University, Germany;*
*Applied Biology, HAS University of Applied Sciences, the Netherlands.*

Many simultaneous hermaphrodites choose to mate as male or female upon copulation, contrasting with pre-determined mating roles in separate-sexed species. This sex role decision in simultaneous hermaphrodites reflects their sex allocation at the behavioral level, and allows to examine reproductive strategies between different life stages or conditions. It is widely believed that larger individuals prefer to act as females, because they have higher reproductive resources, and produce more eggs. Hence, previous studies predominantly focused on effects of body size on sex role decisions, but have excluded or ignored other confounding traits, such as age. Therefore, we examined the effect of age and size on sex role decisions in a freshwater snail species, Lymnaea stagnalis. We paired snails of different types (young/old or small/large) to see which individuals act as male first. Our results show that young and small individuals tend to perform the male role first. Furthermore, small snails allocated proportionally more to their male function, based on weight of reproductive organs. However, large and/or old individuals did not perform better as females, in terms of egg production and reproductive allocation. These findings suggest that the behavioral output of sex allocation requires further attention to understand reproductive strategies in simultaneous hermaphrodites.

# Does local resource competition select for less female biased sex ratios under local mate competition in spider mites? (52590)

**Alison Duncan**, Celine Devaux, isabelle Olivieri, Sara Magalhães.

*University of Montpellier 2;*
*University of Montpellier 2;*
*University of Montpellier 2;*
*University of Lisbon.*

Sex allocation decisions pertain to parental investment in male versus female offspring. Local mate competition (LMC) occurs in sub-divided populations, in which closely related males compete for mates. LMC selects for mothers to produce a lower proportion of sons, which acts to reduce competition between related males as well as to increase the number of mates
per son. However, this prediction relies on the absence of competition among sisters for resources (LRC), which is achieved by the dispersal of females following mating. We thus expect the offspring sex ratio to be less female biased under both strong LMC and LRC (between females), than under LMC alone. We will present results of a selection experiment testing these predictions by comparing how high and low levels of female dispersal (mimicking LRC levels) under strong LMC impacts the evolution of female sex allocation behaviour in the spider mite *Tetranychus urticae*.

Poster session B - MAX 413

**Local mate competition: the role of population viscosity, fecundity, and mating system. (52874)**

**Antonio M. M. Rodrigues**, Andy Gardner.

*University of Cambridge; University of St Andrews.*

The extremely successful interplay between theoretical and empirical research into the sex ratio has been a touchstone for the study of evolution by natural selection. Central to the study of the sex ratio is local mate competition (LMC). LMC theoretical and empirical work have shown that females should produce female-biased sex ratios to prevent competition for mates among related males. Two independent extensions of LMC theory have produced two important predictions that have been the focus of extensive empirical testing: both population viscosity and variation in fecundity among breeding mothers have no impact upon the number of sons each mother produces. We will show under which conditions these two predictions hold. Specifically, we will show how the conjunction of population viscosity and variation in fecundity among breeders one the hand, and deviations from the monogamous mating system on the other hand, can break down these two invariance results. Our study highlights the need for further work on the impact of population viscosity and of individual quality on sex allocation in particular, and on social evolution in general.

Poster session B - MAX 413

**Sex allocation, plasticity and the preference for the male role in simultaneous hermaphrodites (52935)**

**Maria Cristina Lorenzi**, Massimiliano Santi, Stefania Meconcelli.

*Laboratoire d'Ethologie Expérimentale et Comparée, University of Paris13, France;*
*Department of Life Sciences and Systems Biology, University of Turin, Italy.*

Simultaneous hermaphrodites have both male and female functions. According to theory, sexual selection should favor hermaphrodites that shift their reproductive resources between sexual functions depending on mating-group size. Although often tested at the population level, sex allocation theory has been rarely tested exposing the same individual to different levels of mating opportunities in subsequent time periods, thus really testing individual
plasticity.

We tested individual plasticity in female allocation in iteroparous, simultaneously hermaphroditic polychaete worms that are obligate outcrossers and alternate sex roles in subsequent reproductive events. We exposed focal hermaphrodites to weekly changes in mating opportunities, varying either their opportunities to mate as both males and females or competition for the male role (controlling for density). Finally, we exposed worms to simulated weekly changes in mating opportunities by manipulating chemical signals hermaphrodites use to assess partner and/or rival numbers.

Results showed that wherever either real or simulated opportunities to mate as males, hermaphrodites produced fewer eggs, irrespective of density, suggesting no preference for the female role.

These results support theoretical predictions on sex allocation plasticity in hermaphrodites, and show that hermaphrodites may have a preferred sex role. These results have implications for understanding the evolutionary transitions hermaphroditism/separate sexes.

# Experimental evolution of male harm and female resistance in Callosobruchus maculatus. (51666)

Eduardo Rodriguez-Exposito, Francisco Garcia-Gonzalez.

Doñana Biological Station, Spanish Research Council CSIC; Centre for Evolutionary Biology, School of Animal Biology, Nedlands, University of Western Australia.

The interests of the two sexes when it comes to reproduction are expected to diverge in species that are not genetically monogamous. This sexual conflict can lead to sexually antagonistic coevolution. Theory suggests that the intensity of sexual selection and sexual conflict should modulate this coevolutionary process, but empirical evidence for sexually antagonistic coevolution is limited to a few species. The bean beetle Callosobruchus maculatus is a common model system in the study of sexual conflict. The genitalia of males in this species exhibit spines that damage the female reproductive tract. As a result, females are expected to develop counter-adaptations to minimize the costs imposed by mating, and indirect evidence for this evolutionary response comes from comparative studies across species in the genus. We have used experimental evolution to assess the evolution of male harm and female resistance in populations of bean beetles in which sexual selection and conflict was present or absent. Divergence in male harmful adaptations was analyzed by investigating fitness (Lifetime Reproductive Success) in females from outside the selection experiment that were mated to males from the selection treatments. The impact of sexual selection and conflict on the evolution of female resistance was also assessed.

# Investigating the contribution of different developmental and breeding ecologies to mediating sexual conflict in laboratory populations of D. melanogaster. (52015)
Inter-locus sexual conflict arises over traits that are expressed during reproductive interactions between the two sexes and have different fitness consequences for them. Reproductive fitness is determined by traits expressed in adults, largely shaped by their developmental ecology. Ecological changes experienced by an organism during development as well as in the adult stage influence reproductive traits. Many studies have examined the impact of different adult ecologies (levels of intra-sexual competition) on sexual conflict, using experimental evolution. Our work focuses on studying differences in sexual conflict between two types of lab-adapted D. melanogaster populations that experience different ecologies, both during development and as adults during breeding; one is selected to a) develop faster, and b) reproduce sooner, than the other. Our results suggest a large contribution of reduced body size (a correlated response to selection on rapid development) to changes in sexual conflict. Additionally, we are attempting to determine the effect of different breeding ecologies on sexual conflict, given large differences in mating and courtship rates between our experimental populations. To understand the specific roles played by these selection pressures, we are also studying populations experiencing completely relaxed selection for rapid developmental, but either ‘control’ or ‘selection’ breeding ecology.

Intralocus sexual antagonism in a hermaphroditic flatworm (52056)

Anna K. Nordén, Jessica K. Abbott.

Section for Evolutionary Ecology, Department of Biology, Lund University.

Sexual antagonism occurs when the same allele for a gene has opposite fitness effects for females and males. Although generally studied in sexual organisms, sexual antagonism may occur in hermaphrodites and may be one means to maintain genetic variation.

To investigate this, we measured the response to sex-limited evolution in populations of the flatworm Macrostomum lignano (a free-living flatworm) to determine if hermaphrodites can evolve sex-differentiated chromosomes. A GFP locus incorporated into the worm's DNA is used as a dominant sex-determining gene by letting it pass through either eggs ('female' treatment) or sperm ('male' treatment) in each generation. After ten generations we measured the response in each treatment with a fitness assay.

Additionally, we used a standard paternal half-sib design to measure sexually antagonistic genetic variation in M. lignano, allowing us to look at the heritability of fitness via male and female sex roles.

We present data on the response to sex-limited experimental evolution as well as the heritability of fitness via male and female sex roles. Preliminary data suggest that sexually antagonistic genetic variation in populations of M. lignano is heritable, and that there is a negative relationship between the heritability of fitness via male and female sex roles.
# The demographic consequences of evolution of female polymorphisms in damselflies (52065)

**Yuma Takahashi**, Suzuki Noriyuki, Masakado Kawata.

Tohoku University; Rissho University.

The effect of evolutionary changes in traits and phenotypic diversity on ecological dynamics has received much theoretical attention. However, the mechanisms and demographic consequences in the natural condition are largely unknown. Theoretical model incorporating key features of the sexual interaction suggests that the evolution of female-limited color polymorphism in damselflies can alter demographic dynamics by relaxing sexual conflict. Field data and mesocosm experiments using a damselfly Ischnura senegalensis demonstrates that the evolution of increased phenotypic diversity reduces overall fitness costs to females from sexual conflict, which in turn increases productivity, density and stability of a population. Here we analyzed the further ripple effects the evolution of female color polymorphisms on demographic dynamics, such as distribution range and extinction risk, in some damselfly genera. Irrespective of genus, polymorphic species have wider distribution ranges than monomorphic species. The extinction risks of polymorphic species were lower than that of monomorphic ones. Our study suggests that increased phenotypic diversity can enhance population sustainability and thereby influence community dynamics and macroevolutionary processes.

# Female limited X-chromosome evolution reveals non-additivity of sexually antagonistic traits (52099)

**Jessica Abbott**, Katrine Lund-Hansen, Edward Morrow.

Lund University; University of Sussex.

The concept of sexual antagonism has become key to our understanding of sex chromosome evolution, with the X chromosome being of particular interest for a number of reasons. X-linked loci are known to contribute to the evolution of complex traits, the X is expected to be a hotspot for sexual antagonism, and there are clear predictions regarding the dominance properties of X-linked sexually antagonistic loci. We have therefore carried out a female-limited X-chromosome (FLX) evolution experiment in Drosophila melanogaster, where expression of the wildtype X has been restricted to females for over 30 generations with the help of an FM balancer chromosome. We had two aims with this experiment: to quantify the nature and magnitude of the response to sex-specific selection on the X, and to determine whether X-linked sexually antagonistic loci are preferentially non-additive in nature. We found that a number of traits that have previously been characterized as sexually antagonistic responded to the selection, including fitness, body size, and gene expression. By comparing females that were heterozygous and homozygous for the evolved X's we also show that many
traits showed evidence of non-additivity. We thereby confirm many of the predictions about
the genetic architecture of X-linked traits.

# Divergence of Drosophila melanogaster populations in female sensitivity to sex-peptide (52107)

Kristina Wensing, Claudia Fricke.

*Institute for Evolution and Biodiversity, University of Münster.*

Sexual conflict is hypothesised to be an important driver of divergence in reproductive traits between conspecific populations. Female Drosophila melanogaster pay a fitness cost due to multiple mating that is mainly caused by receipt of the sex-peptide. This short peptide is produced in the male accessory gland and transferred to the female at mating. Previous research has shown that females can evolve resistance against male harm however the extent to which D. melanogaster populations might diverge in their sensitivity to sex peptide has not been studied before. Here I fill this gap in our knowledge by testing for divergence in female resistance to sex-peptide by phenotypically comparing cost of mating effects in different D. melanogaster populations. I exposed females of three different populations continuously to standardised males unable to produce sex-peptide or control males throughout their whole life. I measured survival, lifetime reproductive success, and mating frequency and used those variables to calculate and compare a fitness index across the different populations. Divergence in female sensitivity to sex peptide between the different populations may reflect differences in patterns of sexually antagonistic coevolution, underlying genetic variance and/or mating dynamics.

## “Exploring the Genetic Basis of Intralocus Sexual Conflict in Drosophila” (52175)

Tanya Pennell.

*University of Sussex.*

Males and females often optimise fitness differently, and can therefore require differential gene expression to reach their respective optimal trait values. When this cannot be achieved, an evolutionary tug-of-war ensues between the sexes, where they select for different alleles at the same genomic locus (known as intralocus sexual conflict, IASC). This acts to maintain alleles in a population that have opposite fitness effects for male and females. Although fitness effects of IASC have been quantified, its genetic basis remains largely unexplored.

We use hemiclonal analysis to create 223 lines of Drosophila melanogaster, where a genomic haplotype is shared between individuals within a line. This will enable us to quantify the sex-
specific fitness consequences of expressing such haplotypes, and to identify the level of IASC that exists in our laboratory adapted population. Combined with whole-genome sequencing data from each line, we can also perform a genome-wide association study to identify genes associated with IASC.

Furthermore, I explore how environmental change can impact the level of IASC within our population. This could provide an insight into selection pressures that affect sexually antagonistic genes, and how this might subsequently alter the dynamic of conflict resolution.

## Poster session B - MAX 413

# Are males in old age still competitive? Age-dependent sexual conflict in Drosophila melanogaster (52180)

**Hanna Ruhmann**, Claudia Fricke.

*Institut for Evolution and Biodiversity.*

In most species males and females have divergent reproductive strategies. When traits are favored by one sex but cause fitness costs in the other sex, sexual conflict can occur. Evidence is accumulating that not just female but also male age influences reproductive success. We are interested in studying how ageing might affect the expression of a sexual antagonistic trait in males and how this might alter sexual conflict dynamics.

We conducted studies to investigate the reproductive success of ageing males in Drosophila melanogaster with a special focus on accessory gland proteins and their known induced phenotypic responses. We focused on the sex peptide and ovulin, as particularly sex peptide is involved in mediating sexual conflict between the sexes. Using the ELISA method we quantified how much of these proteins males of different ages transfer to females and detected significant differences between the ages.

We determined that the ability to gain a first mating with a virgin female, to prevent females from remating and the competitive power of a male changes significantly over his lifetime. Hence age significantly affects male reproductive success, however this decrease is not constant across male age and already shows a first dip in intermediate aged males.

## Poster session B - MAX 413

# Sexually antagonistic genetic variation in a simultaneous hermaphrodite (52237)

**Tim Janicke**, Elodie Chapuis, Stefania Meconcelli, Nicolas Bonel, Patrice David.

*Centre d'Ecologie Fonctionnelle et Evolutive, CNRS-UMR 5175 ; IRD, UMR 186 "Résistance des plantes aux bioagresseurs"; Department of Life Sciences and Systems Biology, Università di Torino; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca.*
Simultaneous hermaphrodites express both sex functions at the same time offering unique forms of sexual conflict to arise. These include conflicts over the sex role that both interacting individuals adopt when mating and the manipulation of the partners' sex allocation by the sperm donor. Over the last two decades, significant strides have been made in characterizing these and other sexual conflicts in simultaneous hermaphrodites but until now very little is known about intra-locus sexual conflicts in these organisms, which are thought result from opposing fitness effects of an allele when expressed in a sperm donor and a sperm recipient. Here, we report an empirical test of intra-locus sexual conflict in the simultaneously hermaphroditic freshwater snail *Physa acuta*. We explored pre- and post-copulatory reproductive performance of the male and female sex function and tested for sexually antagonistic genetic variation of several fitness components. This was done under varying levels of food availability using a full-sib breeding design.

## Intralocus sexual conflict and the evolution of sexual dimorphism - a large scale approach (52312)

**Maja Tarka**, Christophe Pelabon, Thomas F. Hansen, Bernt-Erik Sæther.

*Center for Biodiversity Dynamics, Norwegian University of Science and Technology (NTNU), Trondheim, ; Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway.*

Males and females often have different adaptive peaks due to differences in reproductive roles. However, most traits are controlled by the same genes in both sexes, which manifests as strong cross-sex genetic correlations. Such correlations are expected to hamper the independent evolution of each sex towards its adaptive peak, causing intralocus sexual conflict. Mitigation or resolution of intralocus sexual conflicts can be achieved by a decreased cross-sex genetic correlation and hence the evolution of sexual dimorphism. However, very few studies have investigated the relationship between sexual dimorphism and the strength of cross-sex genetic correlations. Furthermore, genomic imprinting and differences in genetic variance among sexes could also explain the evolution of sexual dimorphism despite strong cross-sex genetic correlation, but these hypotheses have never been broadly tested. We investigate these different hypotheses using published data on sexual dimorphism and additive genetic variances and cross-sex covariances. In these analyses, we take particular care of using proper standardization methods and accounting for errors of the estimates.

## Parallelism in sex-biased gene expression (52361)

**Kirsten M Jalvingh**, Zoe Dumas, Tanja Schwander.

*University of Lausanne.*
Sexually antagonistic selection can cause gene expression differences between males and females in order to help resolve genetic conflict. The type of genes that can be subject of sexually antagonistic selection range from genes associated with sex-specific tissues to genes related to life-history and behavior. However, some genes may display similar sex-biased expression across related species, while others are under sexually antagonistic selection only in isolated species. In this study we explore sex-biased gene expression in the Timema clade of stick insects. Using RNA-seq we quantify sex-biased gene expression in four different species in the same clade, to detect parallel and divergent patterns in gene expression differences between males and females. This allows us to examine which gene networks are consistently associated with sex-biased gene expression and which ones are subject to species-specific sexual selection.

**Not a fair share; female house finches build and protect the nest from parasites using cigarette refuse, butt... (52385)**

**Monserrat Suárez-Rodríguez**, Constantino Macías Gracia.

*Instituto de Ecología, Universidad Nacional Autónoma de México.*

Several species exhibit phenotypic traits which apparently represent recent adaptations to urban environments. One potential adaptation in Passer domesticus and Carpodacus mexicanus is the use of discarded cigarette butts to line their nests and thus reduce ectoparasite load. In C. mexicanus butts in nests promote growth but also genotoxic damage to nestlings. As parents are in contact with butts during nest construction and attendance, we predicted that they also exhibit genotoxicity at an intensity that should co-vary with exposure, itself a function of 1) amount of cigarette butts brought to the nest, and 2) parental behaviour. Analyses of blood samples taken at four times between egg-laying and chick fledging revealed that damage in female C. mexicanus, which do all the building, is positively associated with the amount of cigarette butts in the nest, and is greater shortly after building the nest than later on. Males, which do not participate in nest-building, showed much less genotoxic damage. It is uncertain whether genotoxicity has long-term negative consequences for short-lived passerines, but if it does, then the way parental roles are partitioned between sexes in this species would mean that the cost of this urban antiparasite strategy is largely borne by the females.

**Do asymmetric paternal effects on offspring size reveal male manipulation of maternal investment? (52386)**

**Yolitzi Saldivar Lemus**, Constantino Macías Garcia.

*Instituto de Ecología, Universidad Nacional Autónoma de México.*
Where embryos can influence maternal investment, paternal genetic manipulation may evolve, prompting the evolution of maternal countermeasures. A way of detecting such coevolution is to examine crosses between populations, as asymmetric embryonic growth may occur upon secondary contact if the coevolution is no longer matched. Appropriate models include matrotrophic fish, where maternal investment is an important component of life history. We sought evidence of asymmetry in reciprocal crosses between two distant populations of the Amarillo fish (Girardinichthys multiradiatus): Zempoala (Z) and San Matías (M). Whereas offspring from M females and Z males were indistinguishable from their controls (M-M), offspring from Z females and M males were bigger and heavier than their controls (Z-Z). Hybrid vigor cannot explain this difference, since M-Z offspring were smaller than those of Z-M. It is also unlikely that Z females found M males more attractive and thus preferentially invested on their offspring, because females from both populations prefer sympatric males. Our data agree with expectations if antagonistic coevolution in M promoted enhanced male epigenetic manipulation of female reproductive allocation coupled with enhanced female resistance, in comparison with Z. This preliminary conclusion calls for evaluation of the pattern of expression of genes responsible for embryonic growth.

# Temporal dynamics of sex-biased gene expression in an annual plant (52412)

**Guillaume Cossard.**

*University of Lausanne.*

Most flowering plants are hermaphroditic, but separate sexes have recurrently and independently evolved in about half of angiosperm families. The separation of sexes in plants, as in animals, is associated with two potentially related processes: the frequent evolution of sex chromosomes; and the evolution of sex-biased expression. Both processes are thought to allow a divergence in phenotype between males and females, either by confining sexually antagonistic genes to the non-recombining region of sex chromosomes, or through the differential expression of the same genes between sexes. A key question of the latter process concerns when during development differential gene expression first becomes evident. This is particularly interesting in plants that lack a germ line: divergence in phenotype might be expected to show itself most strongly only during and after flowering, particularly if secondary sexual dimorphism is the outcome of different sex allocation patterns between the sexes. Here, we report dynamic patterns of sex-biased gene expression in meristematic tissues using RNAseq, from the seedling stage through to the onset of flowering in the dioecious herb Mercurialis annua. We highlight two key results: (I) sexual dimorphism in gene expression occurs prior to flowering; (II) at reproductive stage, the number of male-biased genes dramatically increases.

# When caring evens out between the sexes (52452)
Isabel Salome Keller, **Olivia Roth**.

GEOMAR.

Sexual immune dimorphism evolved upon a resource allocation trade-off between investment into immune defence and sex-specific life-history traits. In conventional parental investment roles males maximize their fitness by allocating resources towards sexual selection while females need to elongate their life span to achieve the same gain. The larger this differential allocation between males and females the more pronounced the display of sexual immune dimorphism.

We suggest sexual immune dimorphism to depend on parental investment and thus to diminish if both sexes provide a similar degree of parental investment. Using biparental and maternal mouth-brooding cichlids of Lake Tanganyika we examined the correlation between immune competence and parental investment strategies. Predicting that biparental mouth-brooding species will have a less distinct immune dimorphism than maternal mouth-brooding species consequential to the mentioned resource allocation trade-off. Cellular immune parameter measurements and immune gene expression of three biparental and four maternal mouth-brooding species suggest sexual immune dimorphism to disappear in biparental mouth-brooders and a generally higher immune competence baseline than in maternal mouth-brooders. Those results imply that parental investment levels out sexual immune dimorphism and that strength of immune system might be coupled to parental investment levels.

Poster session B - MAX 413

**Is sexually antagonistic selection causing the replacement of a sex chromosome system in Podisma pedestris? (52461)**

**Hannes Becher**, Richard A Nichols.

*Queen Mary University of London, School of Biological and Chemical Sciences.*

We describe the identification of sex chromosome-linked markers in P. pedestris, in order to address key questions about the evolution of sex chromosomes, by studying their penetration through hybrid zones. This species has an ancestral X0 sex chromosome system, and a derived neo-X/neo-Y system produced by an X-to-autosome fusion event. The analysis of sex-chromosome clines in the hybrid zone can reveal if neo-Y chromosomes have been subject to sexually antagonistic selection, which would fuel their penetration into the ancestral race. Thus, we can ask if we are witnessing the replacement of a sex chromosome system in this alpine grasshopper driven by this form of selection.

Poster session B - MAX 413

**Pollen dispersal affects the evolution of sexual dimorphism (52503)**

**Jeanne Tonnabel**, Agnès Mignot, Ophélie Ronce, Isabelle Olivieri.
Sexual antagonist selection is deeply studied in animals. Whether the same selective pressures, such as male-male competition, also shape sexual dimorphism in plants is open to question. Here, we test the hypothesis that male-male competition in plants can be mediated by pollen dispersal strategies which contrasted evolution can consequently affect the evolution of sexual dimorphism. Conversely to wind-pollinated species, we expect, in insect-pollinated species, that males displaying morphologies more similar to females would be more efficient competitors due to insect recognition mechanisms. Using a newly reconstructed phylogeny for the genus Leucadendron (Proteaceae) and robust methods that account for phylogenetic uncertainty, we show that both the degree of sexual dimorphism and pollen dispersal strategies are convergent across the evolutionary history of the genus. By comparing models of trait evolution including, or not, correlated evolution, we show that insect-pollinated species tend to evolve decreased sexual dimorphism compared to wind-pollinated ones. This macro-evolutionary study suggests that pollen dispersal strategies through male-male competition can affect sexually antagonist selection. At the micro-evolutionary scale, we are currently studying sexually specific selective gradients in a population of the species Leucadendron rubrum using genetic and spatial data to estimate male and female fecundities.

# The architecture of sexually antagonistic genetic variation (52720)

**Karl Grieshop.**

Intralocus sexual conflict (IaSC) is an emergent property of having two sexes sharing one genome. Because males and females experience different selection pressure(s), there exist sexually antagonistic (SA) loci at which alternative allelic variants are favored oppositely between the sexes. Despite growing interest over recent decades, answers to some of the most basic questions regarding IaSC remain unclear. We previously documented a population of the seed beetle, Callosobruchus maculatus, to be dominated by SA genetic variation (having a negative intersexual genetic correlation for fitness). We have now generated a panel of inbred lines from that SA population, with which we have performed a diallel cross—the most powerful quantitative genetic approach to partitioning variance among its many origins. The data generated from this breeding design will provide insight to several of the voids in our understanding of IaSC, such as the extent to which the underlying genetic architecture for fitness is shared between the sexes, the extent to which that shared genetic architecture is SA, whether or not variances in the additive genetic contribution to fitness are different between the sexes, and the process by which IaSC might maintain genetic variation for fitness.
# Males increase their fitness with high MHC diversity whereas females do not: sexually antagonistic selection on immunity genes? (52734)

**Jacob Roved**, Dennis Hasselquist, Bengt Hansson, Helena Westerdahl.

Lund University.

Host-pathogen interactions has rendered much recent interest, with a number of hypotheses proposed to explain the complex dynamics and selection patterns on hosts and their pathogens. The highly polymorphic genes of the major histocompatibility complex (MHC) have been assigned a major role in the evolution of host defense against pathogens. Heterozygosity in MHC genes has been hypothesized to be favorable conferring protection to a wider range of pathogens. The recent development in DNA sequencing techniques now enables screening of MHC genes also in animals with many loci and high diversity. We have used massively parallel amplicon sequencing to investigate the impact of within-individual MHC class I variation on Darwinian fitness in a wild population of great reed warblers (Acrocephalus arundinaceus). The number of MHC alleles per individual predicted relative offspring survival, but with opposite effects between the sexes, suggesting sexually antagonistic selection. Males showed a significant positive relationship between MHC allelic diversity and the proportion of recruiting offspring, whereas in females this relationship tended to be negative. A possible explanation for the sexual antagonism could be that females with high MHC allelic diversity are more susceptible to autoimmune reactions, which may have adverse effects on parental care and maternal effects.

Poster session B - MAX 413

# Evolutionary consequences of male attraction to warning patterns in mimetic butterflies. (52895)

**Richard Merrill**, Chris Jiggins.

University of Cambridge; University of Cambridge.

The warning patterns of Heliconius butterflies are a textbook example of ecological adaptation. Because predators learn to associate particular patterns with unpleasant experiences, an individual's risk of predation decreases as the local density of its warning pattern increases. However, Heliconius warning patterns are known for their diversity and the establishment of entirely new phenotypes is paradoxical under strict number-dependent selection. During periods of relaxed selection, drift may allow new variants to rise above a threshold density until mimicry selection takes over. Here, I consider an alternative hypothesis. We have shown that male Heliconius use warning patterns as a mating cue. As a result, mated females may suffer fitness costs if these cues lead to harassment by males during oviposition or foraging. I present a series of experiments testing whether novel patterns may allow females to resist costs imposed by males. In addition, individual-based simulation models, informed by the ecology and genetics of Heliconius, imply that male harassment could have played an important role in the diversification of warning patterns. Sexually antagonistic selection appears to be a viable alternative (or addition) to genetic drift to explain the evolution of novel warning patterns in Heliconius butterflies.
# Evolution of interacting reproductive behaviours in burying beetles
(Nicrophorus vespilloides) (51749)

**Nick Royle**, Mauricio Carter, Alastair Wilson, Emma Davey, Allen Moore.

*University of Exeter; University of Georgia.*

Reproductive behaviours involve social interactions not just between males and females (inter-sexual), but also between individuals of the same sex (intra-sexual). Social interactions provide the potential for Indirect Genetic Effects (IGEs), which occur when genes expressed in one individual affect how genes are expressed in an interacting individual and can affect how traits evolve. However, few studies have considered IGEs arising from both inter-sexual and intra-sexual interactions simultaneously. Here we use experimental populations of burying beetles (Nicrophorus vespilloides) that have experienced directional selection on mating rate for 18 generations to test for the presence of IGEs on male reproductive behaviour under different male-male competitive scenarios. Males selected for high mating rate are more socially sensitive to male-male competition than males from lines selected for low mating rate. We found that Direct Genetic Effects (DGEs) are more important sources of genetic variation in mating rate of males than the genetics of social partners (IGEs), but the reverse is true for resource-holding (dominance) behaviours (IGEs are more important than DGEs). Our results highlight the importance of considering social context in order to understand how reproductive traits evolve in species with intra-sex competition.

# Once-a-year coordinated dispersal in subsocial beetles reduces inbreeding rate
(51890)

**Ally Harari**, Hadass Steinitz, Martin Tremmel, Daphna Gottlieb, Yael Lubin.

*The Volcani Center; 2. Haifa University, Israel; 3. Ben Gurion University of the Negev, Israel.*

Sub-social female beetles of the haplodiploid palm-seed borer, Coccotrypes dactyliperda, enter a date seed and establish a colony in which up to five generations may overlap and sisters help tend the young. In most cases, females that leave their natal seed are already mated, but if virgin, the foundress lays a small clutch of eggs that develop into males. After mating with her son, her daughters mate with their brothers, thus a high rate of inbreeding is common. In accordance with Hamilton's (1967) LMC prediction a highly female-biased sex ratio is expected. However, once-a-year, in various populations and coinciding with the high availability of date seeds dropping from the trees, the beetles' behavior is completely changed: Single-sex cohorts of males or females are produced and larvae do not share the typical, common breeding gallery, but each bores its own tunnel and pupates in its own excavated cell. Beetles leave the seed as virgins, outbreed on the way to or in a new seed and,
again, in accordance with Hamilton's (1967) LMC prediction, produce significantly less female biased offspring in the following generation.

# Kin selection and male-male competition: geographic variation in male-male lethal fighting in a social spider mite (51936)

**Yukie Sato**, Martijn Egas, Maurice Sabelis.

*University of Tsukuba; University of Amsterdam.*

Inclusive fitness theory predicts that the intensity of male-male fight over mates varies with relatedness of the males. Specifically, assuming that competition among males is local, the relationship between aggression and relatedness is predicted to be dome-shaped. However, this prediction has rarely been tested in natural populations. Here, we study the relation between relatedness and male-male aggression in colonies of the social spider mite Stigmaopsis miscanthi. This mite forms colonies on Chinese silver grass, constructs woven nests on the undersurface of grass leaves, and lives within the nests in kin groups. Inside nests, males may kill rival males to establish their own harem. Male-male aggression varies among populations. We measured male-male aggression in 25 mite populations across a wide geographic range between Taiwan and Japan, using winter harshness as a proxy of genetic relatedness among nest members in this mite species. Our results show that male-male aggression peaks at intermediate relatedness. This result conforms qualitatively to predictions from inclusive fitness models that incorporate local competition, thereby highlighting the importance of the scale of competition.

# Learning to tell the differences: When can mate-choice copying facilitate hybridisation? (52019)

**Gonçalo S. Faria**, Inês Fragata, Pedro Simões, Sofia G. Seabra, Marta A. Santos, Margarida Matos, Susana A. M. Varela.

*CE3C - Centre for Ecology, Evolution and Environmental Changes, FCUL.*

Mate-choice copying (MCC) by females occurs when they obtain information about the performance of a male, increasing or decreasing their preference for that male, accordingly. MCC has been suggested to cause reproductive isolation between populations with different mate preference traditions. However, the opposite scenario can also occur, if invader individuals copy the choices of natives, leading to hybridization events. We studied the hybridization hypothesis using different populations of Drosophila subobscura, originated from the extremes of the species European latitudinal cline: Portugal (PT) and the Netherlands (NL). Half of the females received positive social information about a male from their own population and the other half about a male from a control (lab) population. At generation six,
we saw that females had an innate preference for the males of their own population, and that they did not copy. Only after four more generations of convergent adaptation in the lab, PT females, but not NL, started to copy. This suggests that MCC does not facilitate hybridization at an early phase after invasion, and that it may be selected in nature only under specific ecological and social contexts, supporting the hypothesis that MCC is most advantageous when males are phenotypically similar.

**The effect of relatedness structure and sexual conflict on the evolution of inbreeding avoidance and preference (52096)**

Alexander Duthie, Jane Reid.

*University of Aberdeen.*

When selecting mates, individuals are widely assumed to avoid breeding with relatives, but theory highlights that inbreeding can increase an individual's inclusive fitness. Inclusive fitness theory predicts sexual conflict over inbreeding such that avoiding inbreeding is often beneficial for females, but not males. Nevertheless, predictions concerning inbreeding conflict are limited by highly restrictive assumptions regarding relatedness structure within populations. We first extend previous theory to show that relatedness structure affects whether inbreeding conflict is predicted when individuals choose mates. We then model a small population of potentially inbreeding individuals in which inbreeding conflict is resolved either in favour of females or males under conditions of biologically realistic relatedness, inbreeding depression in offspring survival, and negative direct selection. We show that inbreeding avoidance often evolves when inbreeding conflict is resolved in favour of either sex. In contrast, inbreeding preference is predicted to be rare and, counter-intuitively, restricted to populations in which inbreeding conflict is resolved in favour of females. Interestingly, this suggests that inbreeding conflict may arise where females benefit by actively preferring inbreeding but males benefit by mating randomly. We thereby provide new predictions regarding sex-specific evolution of inbreeding avoidance and preference and their dependence on resolutions of sexual conflict.

**Sexual conflict over laying patterns in the burying beetle *Nicrophorus vespilloides* (52117)**

Lucy Ford.

*University of Edinburgh.*

Asynchronous hatching (when the offspring from a single reproductive event hatch over an extended period of time) occurs in the burying beetle *Nicrophorus vespilloides*, an insect which provides parental care. Sexual conflict occurs when males and females have conflicting
optimal reproductive strategies. Each parent will try to minimise the amount of parental care it provides, at the expense of the other parent, as long as the total care provided is sufficient for the brood to survive. The sexual conflict hypothesis for the evolution of asynchronous hatching predicts that females may adjust laying patterns to increase male parental effort relative to female effort. To investigate the influence of laying pattern on the duration of care provided, I produced synchronous (20 larvae at 0h, with 0h being the time at which the caring individuals' larvae begin to hatch) asynchronous (10 larvae at 0h, 10 larvae at 24h) and highly asynchronous (10 larvae at 0h, 10 larvae at 48h) broods experimentally. The broods were raised with males either present or absent, and the time of desertion was recorded for each parent. I assessed the fitness consequences for the parents and offspring were using measurements of longevity, parental mass change and offspring pronotum width.

## Indirect Genetic Effects on Reproductive Behaviour and Morphology (52166)

Lucas Marie-Orleach, Nadja Burri, Pierick Mouginot, Aline Schlatter, Dita B. Vizoso, Lukas Schärer.

*Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland.; General and Systematic Zoology, Museum and Zoological Institute, Ernst Moritz Arndt University of Gr.*

The trait values expressed by an individual depend on both its genes and the encountered environmental conditions. Because the latter often encompass social interactions with conspecifics, an individual's phenotype may possibly be affected by the specific genotypes of its partners (i.e., "indirect genetic effects"), and can potentially result in a conflict of interest between the social partners. In two experiments where we crossed distinct genetic lines of the free-living flatworm *Macrostomum lignano* we found clear evidence of indirect genetic effects on morphological and behavioural reproductive traits. The genetic line of the partner significantly affected the focal's testis size — which varied up to 2.4-fold — and its propensity to copulate and to perform the postcopulatory suck behaviour that has been postulated to be involved in sexual conflicts over the fate of received ejaculate. Interestingly, we found not indirect genetic effects on copulation duration, a trait compounded from both partners. Overall, our results show that the expression of reproductive traits can be affected by the genotype of social partners. We discuss how such indirect genetic effects are expected to alter the evolutionary trajectories of reproductive traits and mediate the interplay between social evolution and sexual selection.

## Epigenetic machinery underlying paternal genome elimination in Planococcus citri (52210)

Stevie Anne Bain, Laura Ross.
Paternal genome elimination is a genomic imprinting phenomenon found among several insect species, including the citrus mealybugs (Planococcus citri). In sons, the paternally inherited set of chromosomes is silenced and then eliminated from the germline. Since males can only pass on their genetic information through daughters, it is in their interest to female-bias their offspring's sex ratio. However, females have a genetic transmission advantage through sons, as sons can only pass on their maternally inherited chromosomes to any offspring they sire. Thus, a sexual conflict occurs. In an evolutionary context it seems most likely that a maternal factor underlies the process of PGE, since females benefit from a transmission advantage and males suffer a disadvantage. Genomic imprinting in P. citri appears to be regulated by the same epigenetic machinery involved in mammalian silencing and imprinting (histone modifications and methylation), but the molecular details remain poorly understood. Here we study the parent-of-origin specific epigenetic modifications involved using whole genome bisulphite sequencing and immunostaining for histone modifications throughout development. These data help to understand how paternal and maternal chromosomes are distinguished in order to allow elimination of only those paternally inherited by sons.

# Sexual antagonism, cryptic bias, and the evolution of social hormones in bank voles (52397)

**Mika Mokkonen**, Esa Koskela, Eija Lönn, Tapio Mappes, Phill Watts.

Recent evidence indicates that sexual conflict can result in adaptive production of offspring that will minimize the associated fitness costs. However, little is still known about how individuals optimize their reproductive investment in light of the antagonistic fitness effects on offspring sex. To test this question, we bred male and female bank voles (Myodes glareolus) to produce offspring that differed in the length of the arginine vasopressin receptor (avpr1a) and oxytocin receptor (oxtr) promoter-associated microsatellites because these allele lengths regulate their expression. These hormones and receptors affect a variety of socio-reproductive behaviours. We measured the reproductive success and survival of animals with contrasting genotypes in field enclosure experiments (focusing on the effects of avpr1a and oxtr separately), where the social environment was manipulated (density and operational sex ratio). By mapping the parental origins of the alleles in the offspring, we found that both avpr1a and oxtr are selected towards sex-specific optima, indicating they are sexually antagonistic. Furthermore, cryptic sex-ratio bias according to the allele length reduced the associated fitness costs through biased production of the more beneficial sex. We will discuss how sexual antagonism and cryptic bias maintain genetic variation in genes important for modulating social behaviours in reproduction.
# The role of male-male relatedness on sexual interactions in Drosophila melanogaster (52505)

**Sally Le Page**, Irem Sepil, Pau Carazo, Stuart Wigby.

*University of Oxford; University of Valencia.*

The importance of relatedness in social interactions has long been known, yet it is only recently that the ideas of kin selection have been applied to the field of sexual selection. Male Drosophila melanogaster display a 'sexual altruist' strategy, competing less frequently over females when competing against their brother than against an unrelated male. However, when two brothers and one unrelated male are simultaneously presented to the (unrelated) female, the unrelated male has a paternity advantage – an unexpected and as yet unexplained phenomenon.

To determine the evolutionary stability of this advantage, we are disentangling the potentially conflicting effects of male-male competition and female choice that can occur at both the pre- and post-copulatory stages. Whilst we are increasingly seeing effects of relatedness on sexual interactions, it is not yet known whether D. melanogaster use genetic cues or familiarity/environmental cues to discriminate between individuals.

The preliminary data suggest that unrelated males do not experience a mating advantage in a sequential mating system, which may make the 'sexual altruist' strategy more stable, and we are currently elucidating the mechanisms of kin recognition in this species.

Poster session B - MAX 413

# Is dispersal a good strategy? Sibling competition, dispersal and fitness outcomes in humans (52605)

**Aïda Nitsch**, Charlotte Faurie, Virpi Lumma.

*Institute for Advanced Study in Toulouse; University of Montpellier 2, Institute of Evolutionary Sciences of Montpellier; University of Sheffiled.*

Determining the fitness consequences of dispersal and its interplay with sibling interactions is pivotal for understanding the evolution of family living. On the one hand dispersal, could be a strategy to avoid sibling competition, thereby increasing access to competing resources. On the other hand, dispersal could mainly benefit philopatric individuals through a decrease of the intra-familial competition in the natal territory. These two explanations of dispersal imply different fitness outcomes between philopatric and dispersing siblings. Moreover, the intensity of intra-familial competition is likely to influence the fitness outcomes of each strategy. However, studies investigating the fitness outcomes of dispersal according to the intensity of intra-familial competition are lacking. Using a large demographic dataset on humans from preindustrial Finland (n=4,000), we investigated the fitness consequences of dispersal on different indicators of lifetime reproductive success according to sex-specific birth rank. Contrary to our predictions, the negative effect of same-sex elder siblings on reproductive success was similar between philopatric and dispersing individuals for both
males and females. Overall, these findings do not support the hypothesis that the costs and benefits of dispersal vary with intra-sex birth rank. This study has important implications for the evolution of family dynamics, dispersal and sibling interactions.

# Male and mutual sexual imprinting: what strategy is the best? (52617)

Miguel Gomez.

*University of Manchester.*

Sexual imprinting occurs when individuals acquire a preference for mates with a trait observed on a member of the parental generation. Sexual imprinting can have different strategies, depending on which group of the parental generation individuals imprint on. Different strategies have different effects on males and females. When female imprinting evolves, imprinting on their fathers trait allow females to choose the fittest mate. However, the way in which male and mutual sexual imprinting evolves is not well understood. We developed a model to analyse under which circumstances male and mutual sexual imprinting evolves, and which strategies allow individuals to choose the fittest mate. We found that for males, maternal imprinting is the most likely strategy to evolve. When mutual imprinting evolves, is more likely that both sexes imprint on their fathers. We discuss the importance of male and female imprinting interaction, sex-specific recognition and fitness gains in the evolution of the sexual imprinting strategies. Finally, we suggest variability in the population as a novel way for mutual imprinting to evolve.

# Molecular mechanisms of post-copulatory sexual selection in a leaf-cutting ant
(52669)

Joanito Liberti, Ryan Dosselli, Morten Schiøtt, Boris Baer, Jacobus J. Boomsma.

*Centre for Social Evolution, University of Copenhagen; Centre for Integrative Bee Research, University of Western Australia.*

The queens of polyandrous lineages of ants combine promiscuous mating with strict sexual partner commitment when storing sperm for a life-time of up to two decades without re-mating. This poses the evolutionary dilemma that sperm competition may benefit queen fitness just before sperm enters the spermatheca, but will decrease her life-time reproductive success when it continues after irreversible storage. In an earlier study it was shown that this dilemma in the ant Atta colombica is resolved by initially allowing mutual sperm incapacitation between ejaculates, but terminating that via secretions of the queen sperm storage organ*.

We used a controlled artificial insemination experiment and transcriptomics/ proteomics
techniques to identify genes and proteins mediating the interaction between rival ejaculates
and between the sperm and seminal fluid components of
ejaculates with spermathecal fluid. This allowed us to unravel a set of proteins that mediate
post-copulatory sexual selection in an experimentally predictive manner.

* Den Boer, S.P.A., Baer B. & Boomsma J.J. (2010): Seminal fluid mediates ejaculate competition in social insects. Science 327, 1506-1509.

Poster session B - MAX 413

An explicit test for the relative role of pre- versus postcopulatory inbreeding avoidance in an acridid grasshopper (52840)

Michael Haneke-Reinders, Holger Schielzeth, Tim Schmoll, Klaus Reinhold.

*Department of Evolutionary Biology, University of Bielefeld.*

Matings between relatives often lead to inbreeding depression that is ultimately caused by the expression of recessive deleterious alleles. Kin-recognition is an important mechanism to avoid inbreeding. We already know inbreeding avoidance by kin-recognition in many vertebrates but kin-recognition is also observable in insects like ants, bees (social context) and field crickets (mating context). Although grasshoppers often occur in high densities, the avoidance of inbreeding may also be important due to limited dispersal and large family sizes. Here we investigated simultaneously the relative roles of pre- versus postcopulatory mechanisms of inbreeding avoidance in the rufous grasshopper Gomphocerus rufus. We caught grasshopper nymphae in the field and bred full siblings under controlled laboratory conditions. With the F1-generation we performed a double-mating experiment: We offered each female a full-sibling or an unrelated male and (if copulation occurred) we offered a second male of the alternative type after one week and analyzed mating behavior (copulation propensity, latency and duration) and paternity allocation using microsatellite analysis. Matings with two unrelated males served as controls. Furthermore, our double-mating experimental design also allows to test for sex-specific repeatabilities in traits like copulation duration where it is unclear by which sex they are controlled.

Poster session B - MAX 414

The ups and downs of interlinked public goods traits (51672)

Adin Ross-Gillespie, Zoé Dumas, Rolf Kümmerli.

University of Zurich; Swiss Federal Institute of Aquatic Science and Technology (EAWAG);
University of Lausanne.

Public goods cooperation is vulnerable to freeloaders, which, under appropriate conditions, can drive the loss of an otherwise beneficial trait. Yet, many organisms juggle multiple interlinked public goods and the interactions between these multiple traits can rather
complicate their evolutionary trajectories. We explored conceptually how different forms of
linkage between two public goods traits (i.e. uni- or bidirectional stimulation or repression)
could influence one another's selection. We then tested some of our predictions in the context
of the bacterium <i>Pseudomonas aeruginosa</i>'s production of two different iron-
scavenging siderophores, whose regulation is known to be hierarchically ordered. We tracked
production of the two siderophores in lines experimentally evolved for ~300 generations
under different iron-limitation regimes that favour different expression profiles. Strong iron
limitation led to decreases in the dominant siderophore (due to freeloaders) and increases in
the secondary siderophore (due to derepression), while under moderate iron limitation, the
reciprocal pattern did not arise: only the secondary siderophore significantly decreased its
expression. Our results confirm that the nature of regulatory inter-connections between public
goods traits can significantly modulate the course of their evolution, yet also suggest how we
might predict the impacts such complexities will have on phenotypic divergence and
community stability.

Molecular and Genetic Mechanisms Underlying Parallel Loss of Seasonal
Photoperiodism in Sticklebacks (51941)

Asano Ishikawa, Jun Kitano.

National Institute of Genetics.

In temperate regions, organisms can use photoperiods to reproduce during favorable seasons. When surrounding environments are stable across seasons, some organisms lose their seasonality and elongate their breeding periods. We are investigating the molecular and genetic mechanisms underlying loss of seasonality by using different ecotypes of threespine stickleback. Ancestral marine ecotypes show seasonal migration, whereas derived freshwater ecotypes do not migrate and instead elongate their breeding periods. Our laboratory experiments revealed that maturation of testes is triggered by a shift to long photoperiod in marine populations, but is independent of photoperiods in multiple freshwater populations. Whole transcriptome analysis showed that thyroid hormone-stimulating hormone beta 2 (TSHß2) exhibit the highest response to photoperiodic changes in marine populations, but that this response was lost in multiple freshwater populations. TALEN-mediated TSHß2 knockout sticklebacks showed abnormality in testis development, consistent with previous studies showing a substantial role of TSHß2 in photoperiod-dependent reproduction. In some freshwater populations, cis-regulatory mutations explained some of the difference in TSHß2 response. To investigate the adaptive significance of loss of seasonality, we plan to manipulate TSHß2 response by genetically modifying the cis-regulatory region of TSHß2 and measure the fitness under various environments.

Competition between symbiont species – a mechanism for trait loss? (52012)
**Eleanor Heyworth**, Julia Ferrari.

*University of York.*

While phenotypic traits are most often linked to an organism's gene content and expression, they can be influenced by many different factors. Some of the most fascinating examples are the symbiont-mediated traits in insects. Facultative bacteria are ubiquitous across insect species and carry genes that can affect their host's phenotype. When transmission of these symbionts is predominantly vertical, the selection pressure for traits that benefit the host is strong. We use pea aphids (Acyrthosiphon pisum) as a model system for endosymbiont community effects. Beneficial aphid symbionts are well studied and can dramatically increase host resistance to parasitoid wasps, fungi and heat. Infections of multiple species are commonly found in individual aphids, but little is known about how microbial interactions affect host ecology. Our results show that despite double infections being common in aphid populations, the symbionts we used – X-type and Regiella insecticola – revealed unexpected instability when introduced to each other in novel infections, with loss of one symbiont. Using qPCR to track endosymbiont dynamics during vertical and horizontal transmission, we discover evidence for strong competition between the species. This indicates a dynamic system of interaction, resulting in loss and gain of traits through an endosymbiont-mediated horizontal gene pool.

Poster session B - MAX 414

**Oxidative homeostasis and the evolution of tolerance and dependence in insect-Wolbachia symbioses (52108)**

**David Monnin**, Natacha Kremer, Clément Berny, Hélène Henri, Adeline Dumet, Yann Voituron, Emmanuel Desouhant, Fabrice Vavre.

UMR CNRS 5558 Laboratoire de Biométrie et Biologie Evolutive; UMR CNRS 5023 - Laboratoire d'Ecologie des Hydrossystèmes Naturels et Anthropisés.

Symbioses are long-term inter-specific interactions that form a continuum ranging from parasitism to mutualism. Reactive oxygen species (ROS) are molecules able to mediate symbiotic relationships since they can affect the physiology of both host and symbionts. Although detrimental to many cellular components when in excess, ROS also play a role as part of the immune response to infection by microorganisms. As a consequence, the oxidative homeostasis, i.e. the balance between ROS and antioxidant molecules, may be a key factor underlying the evolution of symbioses. As a dramatic example, the dependence of Asobara tabida (Hymenoptera) to Wolbachia for oogenesis may be due to a breakdown of oxidative homeostasis resulting from the adaptation of the host to its symbiont (tolerance). Using Drosophila melanogaster as a model, we show that experimental manipulations of oxidative homeostasis can decrease Wolbachia density and reduce the cost of infection. This suggests that tolerance evolution in insect-Wolbachia symbioses can involve a modulation of oxidative homeostasis. Because of the multifarious effects of ROS, any adaptation involving a modulation of oxidative homeostasis is likely to have many side effects, potentially rendering the host maladapted to the absence of its symbiont, or even completely dependent upon it.
# The genetic architecture of sexual trait decay (52226)

Casper J. van der Kooi, Christoph Vorburger, Tanja Schwander.

*Department of Ecology and Evolution, University of Lausanne; EAWAG, ETH Zürich;*
*Department of Ecology and Evolution, University of Lausanne.*

Changes in life history can induce a shift in selection pressures and thereby render formerly adaptive traits non-functional. Consequently, these non-functional traits are expected to decay, either because the traits are released from selection (i.e. neutral) or because investment can be costly (e.g. in terms of resource investment). In asexual lineages, the traits formerly involved in sexual reproduction are non-functional and often decay, yet it remains unknown whether this decay is the result of many mutations with small effects or few mutations with large effects.

The aim of this study is to infer the level of sexual trait decay and its genetic architecture in asexual lineages of the parasitoid wasp Lysiphlebus fabarum (Hymenoptera: Braconidae). Using the few males that are occasionally produced by asexual females, we introgress alleles from the asexual into sexual lineages and perform mating assays to test the sexual functionality of females. The genetic architecture of decayed sexual traits and various morphological traits is inferred from classical genetic crosses in combination with a mapping approach based on RAD sequencing. Our findings on the genetic architecture of decayed sexual traits are compared with the genetic architecture of other traits.

# Evolutionary shifts in chemical communication: The loss of a sex pheromone (52288)

Jan Buellesbach, Thomas Schmitt.

*Jena School for Microbial Communication; Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg.*

The evolution and maintenance of intraspecific communication channels constitutes a key feature of sexual communication that requires tight coordination between the senders and receivers of sexual cues. However, in the emerging Hymenopteran model organism Nasonia, we were able to detect an unexpected loss of function in an apparently ancestral female sexual cue. Generally in Nasonia, female cuticular hydrocarbons (CHC) function as species-specific sexual cues, enabling males to detect, discriminate and prefer conspecific females. In females of N. giraulti though, one of the most recently diverged Nasonia species, CHC profiles displayed a dramatic shift, greatly contrasting the genetic divergence in the Nasonia species complex. These findings are further complemented by the apparent loss-of-function of female CHC as sexual cues in this species, whereas N. giraulti males retain their perception capabilities as demonstrated by their reaction to heterospecific female CHC. This constitutes
one of the first reports of an apparent deviation from an intact communication system due to
an evolutionary shift and a loss-of-function in the signaller, which the receiver did not adapt
to. The implications of these findings are discussed in the light of the genetic basis of CHC
variation and the potential evolutionary processes underlying and enabling such a shift.

## Recent diversification events in Bicyclus butterflies are generally linked with trait loss (52487)

**Oskar Brattstrom**, Kwaku Aduse-Poku, Ullasa Kodandaramaiah, David C Lees, Paul M Brakefield.

*Cambridge University - UK; IISER, Thiruvananthapuram - India.*

Males of many butterflies have androconia that are specialised wing scales important in courtship and are prime candidates in understanding speciation. Having traditionally been linked with scent communication, recent studies suggest that they also have additional, as yet unknown roles.

The subtribe Mycalesina shows an extraordinary complexity of androconia, especially in the African genus Bicyclus. Mapping these traits across more than two hundred taxa suggests that divergence in androconial number between sister species typically happened through loss. This can be detected as androconia are often arranged as groups of functional units. The more developed structures, such as hairpencils, appear to be fully reduced almost immediately. Less conspicuous units, such as scale patches, disappear more gradually leaving microscopic evolutionary fossils on the wings that help to reveal the ancestral state.

When new androconial traits arise they usually represent a reoccurrence of a type of androconia common within the subtribe. Looking back at older phylogenies where rates of loss and gain were estimated without knowledge of microscopic structural remains these showed a higher rate of gain than of loss. In general, it appears that complex novel traits arise rarely amongst Mycalesina, and when lost they are replaced by more general traits.

## Differential gene expression associated with evolutionary loss of a metabolic trait (52578)

**Mark Lammers**, Ken Kraaijeveld, Peter H. Neleman, Jacintha Ellers.

*Animal Ecology, VU University Amsterdam.*

Over the last decade there has been increased appreciation for the fact that evolutionary
changes are frequently associated with the loss of phenotypic characters. However, the
evolutionary trajectories leading to trait loss are poorly understood, particularly the genetic
changes associated with this important evolutionary process. Parasitoid wasps form an
excellent model system to discover unifying principles that link phenotypic trait loss with
molecular decay in the genome, because of the repeated loss of a key metabolic trait in
parasitoids, the loss of de novo lipogenesis. Although parasitoids are capable of utilizing
dietary carbohydrates to meet immediate energy demands, the conversion of such
carbohydrates to long-term storage in the form of lipids is
impaired even in the presence of excess carbohydrates. Here we present the results of a gene
expression experiment to unravel regulatory changes associated with trait loss. We show
major changes in the transcription of enzymes in the fatty acid biosynthesis pathway, among
others, in the non-lipogenic parasitoid Nasonia vitripennis compared to a species capable of
lipogenesis, Drosophila melanogaster. These results suggest gene regulation as a potential
molecular mechanism underlying trait loss.

Poster session B - MAX 414

Males of a small marine fish reduce the use of one of two courtship signals as a response to aquatic noise (52753)

Karen de Jong, Adrian Klein, Katja U. Heubel.

University of Tübingen; University of Bonn.

The increasing levels of background noise in our oceans may hamper acoustic communication under water. However, because behaviour is often flexible, animals may be able to change their signals to overcome the loss of signal efficacy. Males of a small marine fish, the two-spotted goby (Gobiusculus flavescens), use two different acoustic signals to attract females. We found that when we added experimental noise to an aquarium in a repeated measure design males responded by reducing the use of one of these signals, but not of the other. As a noise source, we used a submersed electromotor which produced a constant noise with a dominant frequency that partly overlapped with the two-spotted goby calls, thus interfering with the signal while allowing us to see when sounds were made. Males reduced the use of the signal that was most overlapped by the noise source, suggesting that they are able to adapt their acoustic signals to the acoustic environment. The reduction of one of the courtship signals may, however, lead to different choices in females and therefore affect the direction or strength of sexual selection.

Poster session B - MAX 414

Gene flow-selection balance and the response of metapopulations to climate
change (51590)

Michael L. Logan, M. C. Duryea, Orsolya Molnar, Benji Kessler, Ryan Calsbeek.

Stellenbosch University; University of Lund; University of Brazil; Dartmouth College.
Progress towards understanding the impact of climate change on natural populations has been hampered by a lack of an evolutionary perspective. Critically, most models assume that populations exist in isolation, ignoring the fact that nearly all populations are connected by some degree of dispersal. This is an important shortcoming because the maintenance of genetic and phenotypic diversity, which are needed for a successful response to climate change, are in large part determined by the balance between natural selection and gene flow. Here, we use the brown anole lizard, Anolis sagrei, to examine how variation in the thermal environment across an island archipelago drives local adaptation in the face of pervasive gene flow. Despite high levels of island connectivity, thermal optima for locomotor performance in each population closely matched the local thermal environment, suggesting local adaptation. Moreover, gene flow was highest between islands with similar thermal environments, irrespective of island area or isolation. These results are consistent with the view that exceptionally strong natural selection can overwhelm the homogenizing effects of gene flow, and that spatial variation in selection generates an ‘adaptive reservoir’ that may buffer species against the negative effects of climate change.

## The role of life history traits in mammalian invasion success (51668)

**Isabella Capellini**, Joanna Baker, William Allen, Sally Street, Chris Venditti.

*University of Hull; University of Reading; University of Hull; University of Hull; University of Reading.*

Why some organisms become invasive when introduced into novel regions while others fail to even establish is a fundamental question in biology, with strong implications given the huge impact of invasive species on biodiversity and economy. A central concept in invasion biology is the sequential nature of invasions along an ‘invasion pathway’. Barriers at each stage should filter species along the invasion pathway, but no study to date has investigated the whole pathway in a single taxon at the global scale. Here we demonstrate how life history traits support population growth across the entire pathway in mammalian invasions at the global scale. Human mediated introductions considerably bias which species have the opportunity to become invasive, as mammals producing larger and more frequent litters over longer reproductive lifespans are far more likely to be introduced. Subsequently, highly productive mammals with longer reproductive lifespan establish self-sustaining populations. Established species that spread exhibit higher reproductive output. Greater productivity thus supports population growth and invasion success, with barriers at each invasion stage filtering species with progressively higher fecundity.

## Temperature-dependent benefits of bacteria for the hatching success of resting eggs of Daphnia magna (51710)

**Alexandra Mushegian**, Elodie Burcklen, Dieter Ebert.
Universität Basel.

The “seed bank” of resting eggs of Daphnia magna and other crustaceans is recognized as an important biotic reservoir affecting the dynamics of aquatic ecosystems, but little is known about the effects of interspecies interactions on the hatching success of these eggs. We performed a series of laboratory experiments manipulating temperature and bacterial environment of resting eggs of Daphnia magna. Unexpectedly, at elevated temperatures (>25° C), resting eggs with no live bacteria on their surface or in their environment had reduced hatching success and correspondingly higher rates of severe morphological abnormalities compared to eggs with bacteria in their environment. These results highlight the complexity of the ecological dimensions of animal development, and indicate that activities of environmental bacteria might be important to consider when predicting the effects of environmental change.

Poster session B - MAX 414

## Empirical evidence that natural selection is not the only mechanism of adaptive evolution (51712)

Pim Edelaar, Adrian Baños-Villalba, David Quevedo-Colmena, Graciela Escudero.

University Pablo de Olavide.

Is natural selection really the only mechanism capable of deterministically driving adaptive evolution? We studied grasshoppers which locally adapt in colour to that of natural soils. A novel, urban habitat has narrow pavements of different colours which are colonised by divergent, cryptic grasshopper populations. We experimentally excluded plasticity as driving the observed divergence. Capture-recapture studies and simulations show that natural selection is also not able to maintain the observed degree of divergence. Manipulation of grasshopper colour using synthetic hormones resulted in the predicted, adaptive change of preferred habitat, both in a small-scale lab assay and a true-scale field experiment. Hence together these data show that individuals, given their colour, preferentially settle and stay on those novel substrates which provide them greater crypsis. Common-garden experiments showed that colour is partly genetically determined. Finally, males detect females over just a few meters, such that choice of type of pavement indirectly leads to assortative mating by colour. We therefore conclude that genetically variable individuals have chosen to colonise those novel habitats to which they were pre-adapted, thereby creating genetically diverged, locally adapted populations. Thus, habitat choice can deterministically drive adaptive evolution, and could do so even if natural selection didn't act.

Poster session B - MAX 414

## Do opposites attract or detract? Direct conflicts between genetic and environmental influences on body size in North American Drosophila (51794)

Michelle Taylor.
University of Exeter.

Populations of a species often differ in key traits. Differences can be explained by genetic variation, plastic responses to the environment or a mixture of the two. However, it is rarely known whether genetic and environmental influences produce the same or different outcomes in trait variation. In the most extreme cases, where genetic and environmental influences directly contradict each other, this may result in maladapted traits across species distributions. We examined this issue by investigating temperature-size relationships in populations of D. pseudoobscura from North America. We used a selection of isolines from each of three populations and reared them in four temperatures that represented the range of environmental temperatures across their geographic range. We found that individuals from all populations had larger wing sizes when reared at colder temperatures, conforming to well-known geographic patterns of temperature and size. However, we also found that flies originating from Northern populations, who routinely experienced a cooler climate, were consistently smaller than their Southern, warmer climate conspecifics when reared under equal conditions. This revealed a direct conflict between genetic and environmental influences on wing size, which may impact on population fitness across the species range.

Poster session B - MAX 414

# The determination of the sensitive parameters to analyze the uncertainty of the terrestrial ecosystem (51811)

Guodong Sun.

LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences.

In this study, we present a new approach to ascertain the subset of those relatively more sensitive and important parameters among the physical parameters. The Lund-Potsdam-Jena (LPJ) dynamical global vegetation model was utilized to test the validity of the new approach. The results imply that nonlinear interactions among parameters play a key role in the uncertainty of numerical simulations in arid and semi-arid regions of China compared to those in northern, northeastern and southern China. The uncertainties in the numerical simulations were reduced considerably by reducing the errors of the subset of relatively more sensitive and important parameters. The results demonstrate that our approach not only offers a new route to identify relatively more sensitive and important physical parameters but also that it is viable to then apply “target observations” to reduce the uncertainties in model parameters.

Poster session B - MAX 414

# Predation pressure accelerates evolutionary response to temperature change (51850)

Michelle Tseng, Mary I. O'Connor.

University of British Columbia; University of British Columbia.
Given the projected increase in mean global temperature, there is a pressing need for research that examines whether organisms can evolve fast enough to adapt to changing climate. While a handful of studies have demonstrated rapid adaptation to temperature, they have all been performed on single species systems and thus their relevance to natural settings is limited. Virtually all organisms live in a community setting, thus understanding how trophic interactions mediate the evolutionary response to environmental change can improve predictions of evolutionary trajectories in nature. Here we report experimental evidence that predation pressure by Dipteran predators (Chaoborus americanus) accelerated the evolutionary response of Daphnia pulex (a freshwater crustacean) to temperature change. Populations selected with predators also evolved elevated phenotypic plasticity to temperature. Together these results reveal that biotic interactions not only modify but enhance evolutionary responses to environmental temperature change.

Determinants of connectivity in the marine environment: a multispecies
approach (51877)

Abigail Cahill, Didier Aurelle, Emilie Boissin, Aurélien De Jode, Emilie Egea, Zinovia Erga, Romain David, Sophie Dubois, Jean-Baptiste Ledoux, Anne Chenuil.

Aix-Marseille Université; Institut Méditerranéen de Biodiversité et d'Ecologie Marine et continentale (IMBE) UMR 7263.

An important step in studying responses to global change is determining the patterns and scale of connectivity among populations. Gene flow and selection are expected to be important and opposing forces governing a species' capacity to respond to changing conditions. In marine invertebrate species, adults are often sessile and populations exchange individuals via dispersal of gametes and larvae. This leads to a general pattern where species that have a long larval period are expected to be more connected than those without larval dispersal. However, in the northwestern Mediterranean Sea (Marseilles, France), even species with relatively long-lived larvae and high dispersal potential show a surprising number of genetic breaks over a small spatial scale (approx. 250 km). We compiled data on genetic patterns, habitat, and life history traits in nine species spanning five phyla. Using a comparative approach and current modeling techniques, we hoped to understand what factors (life history, habitat, environment, etc.) best explain the number and placement of these genetic breaks. By using data from a single area, we minimized the effects of sampling at different sites and instead focused on traits that may influence connectivity, and ultimately local adaptation and responses to global change in these species.

Mapping genetic and species diversity of pollinators to the ecosystem service of pollination across changing landscapes (51975)
**Panagiotis Theodorou**, Josef Settele, Christoph Bleidorn, Oliver Schweiger, Ivo Grosse, Tomás E. Murray, Robert J. Paxton.

*Martin-Luther-University Halle-Wittenberg; University of Leipzig; Helmholtz Centre for Environmental Research – UFZ Halle; National Biodiversity Data Centre, Ireland; German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig.*

Animal pollinators, especially wild bees, are a critical component of our terrestrial ecosystems by providing essential pollination services to many wild and crop plants. However, during the last decades numerous reports have shown declines in numbers of both wild and managed pollinators that can have major ecological and economic consequences. The relationship between species diversity and ecosystem function has been clearly demonstrated in experimental microcosms and field plots with respect to primary productivity but rarely explored across other trophic levels or ecological interactions, including pollination. Moreover, the relationship between flower visitor species diversity and pollination service provision shows little consensus across studies. Here, we study the degree to which genetic diversity of pollinators can predict the ecosystem service of pollination. Using sites that differ in their land use, we map population genetic diversity to community species diversity and their relationship to the ecosystem service of pollination. We use high-throughput DNA sequencing for species diversity assessment and Illumina-based RAD-sequencing for genetic diversity assessment. By incorporating urban/rural paired sites into our experimental design we test whether genetic diversity of functional pollinators is enhanced in structurally complex habitats, including warmer urban sites, and identify potential evolutionary responses of pollinators to climate change.

**Photosynthetic Pathways and Selective Herbivory: A Phylogenetic
Comparative Approach (52029)**

**Erik van Bergen**, Russell Hall, Paul Brakefield, Colin Osborne.

*University of Cambridge; University of Sheffield.*

Mycalesine butterflies have radiated dramatically in Africa, Madagascar and Asia and produced more than 300 extant species. Their larval host plants are nearly always grasses. A major driving process could have been the ability of mycalesine butterflies to invade the empty niches that arose as a result of the evolution of the C4 photosynthetic pathway and the worldwide expansion of C4 grasses in open environments.

In theory, C4 photosynthesis should exert a strong influence on trophic interactions. C4 leaves are predicted to have higher physical resistance leading to higher harvesting and processing costs. In addition, the digestibility and nutritional values of C4 foliage are lower. These expectations led to the hypothesis that herbivores should develop more slowly and have lower fitness on C4 than on C3 leaves (Caswell hypothesis).

Here we test this hypothesis by measuring establishment and growth rates of one species of mycalesine butterflies on a set of 80 different grass species, representing the multiple origins
of C4 photosynthesis together with C3 sister taxa. We aim to investigate if and how herbivore fitness and early development is affected by photosynthetic pathway and evolutionary history of the hosts and test the relative importance of the nutritional value and physical resistance of the grasses on these two herbivore fitness traits.

# Plastic response of a long-lived shorebird to extreme climatic events (52061)

**Liam Bailey**, Martijn van de Pol.

*Australian National University; Netherlands Institute of Ecology.*

Global climate change is expected to increase the frequency and magnitude of previously rare climatic extremes, with potentially negative consequences for affected populations. Phenotypic plasticity may facilitate rapid adaptation to extreme climatic events, but the occurrence of a plastic response will be dependent on an extreme climatic event exhibiting reliable cues, which may not always be the case. As such, the occurrence of plasticity as a response to extreme climatic events still requires empirical assessment. Here, we monitor the nest-site selection process of the long-lived Eurasian oystercatcher (Haematopus ostralegus) in response to increasingly frequent and more extreme high tides, using data covering the past 20 years. We show that the average nest elevation of the population has increased over time as tidal patterns have changed; however, we found this trend was driven most strongly by changes in selection, with low elevation territories being abandoned and left unoccupied, rather than itra-generational changes in nest-site selection. Our results suggest that phenotypic plasticity does not provide a means for the Eurasian oystercatchers to adapt to changing patterns of extreme climatic events. This represents one of the first attempts to empirically test the efficacy of phenotypic plasticity as a response to extreme climatic events.

# Climate change responses in canopy-forming seaweeds (52151)

**Alexander Jueterbock**, Galice Hoarau.

*University of Nordland.*

Canopy-forming seaweeds provide foundational habitat for diverse ecosystems along temperate rocky shores. The seaweeds' centers of adaptive potential in ancient glacial refugia - rich in genetic variation and uniqueness - are highly threatened with extinction from current climate change. To predict the impact of climate change on seaweed meadows in the temperate and sub-polar regions of the northern hemisphere, we used a multidisciplinary approach, integrating Niche Modeling (biogeographic effect), heat-stress experiments (physiological plasticity), and population genetics (evolutionary responsiveness). Our models predicted that suitable seaweed-habitat will open up in the southern Arctic. At the same time, some species of
seaweeds are
likely to disappear in southern Europe before year 2200 - changes that would largely disturb
species interactions and ecosystem services. Population-specific heat-stress responses in
performance and heat-shock protein gene expression suggested local thermal adaptation in the
seaweed Fucus serratus. The seaweed's physiology, however, is likely insufficient to prevent
the predicted habitat loss at its southern distributional edge, where we recorded significant
loss of allelic richness (>12%) over the past decade; along with a 90% decline in abundance.
The remaining key question is whether evolutionary responses, which we recorded in
microsatellite outlier-loci, could save the seaweed's center of adaptive potential.

Poster session B - MAX 414

Broadness of thermal tolerance is linked to decreased virulence in fish pathogen - does climate change alter disease epidemics? (52168)

Roghaieh Ashrafi.

Longer summers associated with climate change are expected to lengthen the period of environmentally borne disease outbreaks. By changing the thermal tolerance of naturally occurring opportunistic pathogens climate change could also alter the virulence of the pathogens. Here, using a multi-locus sequence analysis, temperature dependent growth experiment and virulence experiment, we show that the fish pathogen Flavobacterium columnare trades off virulence with thermal tolerance breadth. High virulence was associated with reduced ability to tolerate a wide range of temperatures. Moreover, ca. 80 clones sampled over ten years across Finnish fish farms seem to be derived from two ancestral lineages and have semi-clonal and epidemic population structure. However, genotypes were independent from the geographic origin and year of analysed isolates. Thermal tolerance data showed no relationship based on geography but genotypes explained thermal tolerance differences in F. columnare isolates. Our results suggest that the link between thermal tolerance and virulence in F. columnare can effectively lead in to the changes of the virulence and disease outbreaks when climate warming proceeds.

Poster session B - MAX 414

Phenotypic responses of a water flea population to rapid environmental
change (52182)

Miia Mannerla, Laura Sartamo, Anu Vehmaa, Ulrika Candolin.

University of Helsinki, Department of Biosciences, Helsinki, Finland; University of Helsinki, Department of Environmental Sciences, Lahti, Finland; Tvärminne Zoological Station, University of Helsinki, Hanko, Finland.

A powerful way to reconstruct past responses of populations to human-induced environmental
changes is to investigate their fossils. Cladocera (water fleas) have been shown to undergo
changes in morphology in response to changes in the environment, and to leave subfossils that
provide valuable material for long term studies of phenotypic changes. We investigated how a common Baltic Sea cladoceran, Eubosmina maritima, has phenotypically changed in response to eutrophication during the past decades. Sediment cores from sites with different eutrophication history have been sampled, and fossils from sediment layers from periods before, during and after the most severe eutrophication have been measured. We will present our results on how morphological changes (such as changes in overall size of the organism and in the length of appendages) correlate with eutrophication induced changes in the food web (such as primary production and predator community). The results will reveal the magnitude and rate of phenotypic responses of this common species to past environmental changes, and thus help to predict its future success in the face of new challenges.

## Do the number of niches limit diversification? (52194)

**Louis du Plessis**, Tanja Stadler.

ETH Zürich.

The amazing biodiversity of life on earth emerges through the evolution of new species. Although diversification is a constantly ongoing process, the rates at which species arise and go extinct are far from constant. Diversity-dependent speciation postulates that speciation is limited by the number of free niches that can be occupied by novel species. Many adaptive radiations show an initial increase in the speciation rate followed by a subsequent slowdown. Although this appears to support diversity-dependence, it is possible that slowdowns are caused by alternative explanations [1].

We implemented a model within the BEAST 2 framework that quantifies diversity-dependent speciation by modeling diversification as a birth-death process with an explicit dependence of the speciation rate on the number of free niches. We look for evidence of diversity-dependent speciation among monomorphic clades within the global bird phylogeny [2]. We further use simulations to explore whether or not the observed slowdowns in the speciation rate can be explained by sampling biases or geographic factors.

[1] Moen D, Morlon, H, “Why does diversification slow down?” Trends Ecol Evol (2014)..

[2] Jetz et al., “The global diversity of birds in space and time” Nature (2012).

## Experimental evolution of metal tolerance in changing environments (52213)

**Florien A. Gorter**, Mark M. G. Aarts, Bas J. Zwaan, J. Arjan G. M. de Visser.

Wageningen University.
Directional environmental change is a ubiquitous phenomenon, with climate change as a notorious example. To investigate the effect of different rates of change on evolution, we grew Saccharomyces cerevisiae for 500 generations in the presence of (i) constant high, or (ii) gradually increasing, concentrations of cadmium, nickel or zinc. We anticipated that, depending on the nature of underlying genotype-by-environment interactions (GxE), these regimes would result in different evolutionary dynamics and endpoints. More specifically, we considered the consequences of magnitude versus reranking GxE. Both types of GxE predict that gradual change, as opposed to abrupt change, delays fitness increase, but only under reranking GxE may evolution under both regimes lead to different endpoints. Our data show that gradual change delays fitness increase compared to abrupt change, but fitness of evolutionary endpoints is the same under both regimes. For cadmium this is due to smaller fitness differences at low metal concentrations (magnitude GxE), while for nickel different isolates are selected at different concentrations (reranking GxE). Whole-genome sequencing uncovered SNPs and structural changes that provide additional support for our hypotheses. Our findings imply that the rate of environmental change and the nature of the stressor are crucial determinants of evolutionary dynamics and outcomes.

# Phenotypic variation between core and edge populations of a range expanding plant species (52311)

**M. Nicky Lustenhouwer**, Jennifer L. Williams, Jonathan M. Levine.

*Institute for Integrative Biology, ETH Zurich; Department of Geography, University of British Columbia.*

Population spread lies at the heart of biological invasions and range shifts with climate change. Spreading populations may evolve rapidly, driven by selection for higher dispersal and fecundity at the invasion front, local adaptation and/or serial founder events.
We studied phenotypic variation between range core and edge populations of Dittrichia graveolens, a Mediterranean annual plant species that is currently spreading into Switzerland. In a common garden experiment in Switzerland, field-collected seeds were sown from 3 Swiss populations from the expanding range edge and from 4 southern and 9 central French populations from the range core.

We found a strong latitudinal gradient in phenology, with plants from the central French and Swiss populations flowering on average 3 weeks earlier than plants from southern France. The Swiss populations had the highest germination, biomass and fecundity in our Swiss common garden, followed by the central and southern French populations. No clear differentiation in dispersal ability was found.

The high germination and fecundity of range edge populations in Switzerland could contribute considerably to their spread velocity. Local adaptation should therefore not be discounted as a force increasing the invasion velocity of spreading populations, even in the absence of dispersal evolution.
# Heterosis and inbreeding depression in alpine populations of Arabidopsis thaliana (52334)

**Marie Roumet**, Widmer Alex.

ETH Zürich; ETH Zürich.

Climate warming is pushing species ranges upwards in elevation. This problem raises interest in studies focusing on adaptation at range margins and on how changes in connectivity among populations may affect their evolutionary trajectory.

The model species Arabidopsis thaliana is a common species in the central European part of its range, where it occurs from sea level of to about 2000m above sea level. In alpine regions, A. thaliana populations are typically small and isolated. Focusing on 6 populations located along an altitudinal gradient in the Swiss Alps, we used controlled crosses to (i) investigate the evolutionary consequences of genetic drift and, (ii) discuss how inter-populations gene flow could affect their evolutionary trajectories.

We frequently observed a fitness reduction associated to selfing (inbreeding depression) and a positive effect outcrossing (heterosis), implying that genetic drift caused the accumulation and fixation of deleterious recessives mutations. We also reported cases where inter- and intra-populations crosses caused reduced hybrid fitness. This last result suggests that the selfing mating system and small effective size of alpine populations of A. thaliana favour the accumulation of genetic incompatibilities; it also highlights the risks associated to gene-flow and the introduction of novel genetic variation into a local pool.

# Environmental variation affects fitness and energetics in nectar-feeding butterflies (52354)

**Kristjan Niitepõld**, Carol Boggs.

University of Helsinki; University of South Carolina.

Changes in environmental conditions alter the availability and distribution of resources, which can lead to changes in population dynamics. When available resources are limited, individuals have to allocate their finite resources among different life-history traits such as movement, foraging, maintenance, and reproduction. We used nectar-feeding butterflies as our study system and subjected butterflies to nutritional stress at different life stages. In addition, we forced butterflies to fly to see how increased energy expenditure affected life-history. We recorded a large number of traits such as egg production, food intake, body mass and lifespan, as well as resting and flight metabolic rate throughout the entire adult life. We found that butterflies conserved their flight capacity when food was scarce. This highlights the importance of flight for butterflies. However, forced flight elevated the rate of metabolic senescence, suggesting that flight is physiologically costly. Flight did not affect reproduction, whereas adult food restriction clearly reduced reproductive output. Interestingly, the strength of the decrease in fecundity differed between species, reflecting life-history strategies and egg composition. Mechanistic studies of resource allocation under stress are therefore needed to
build a comprehensive understanding of how environmental changes affect species-specific
population dynamics of natural populations.

Evolutionary Potential in the Face of Catastrophic Change (52451)

Carol Eunmi Lee, Marijan Posavi, Gregory Gelembiuk, Jane Remfert, Guy Charmantier, Mireille Charmantier-Daures.

University of Wisconsin; Université de Montpellier.

How can we assess whether populations have the potential to evolve in response to
catastrophic environmental change, such as biological invasions, oil spills, or climate change?
To what extent are populations constrained from undergoing an evolutionary response? And
would independently derived populations show evidence of parallel evolution? This talk
summarizes key results from several studies, including laboratory selection experiments and
comparative studies that document rapid evolutionary responses to crude oil from the Deep
Horizon Gulf oil spill, salinity changes during biological invasions, and temperature shifts in
coastal environments. In particular, invasive populations are striking in their capacity to
extend their ranges into novel habitats. Analyzing populations that can invade, relative to
those that cannot, point to the nature of the native range in shaping the evolutionary potential
to undergo habitat shifts. A history of temporal fluctuations in the native range, along with
mechanisms promoting the maintenance of genetic variation, might serve as critical factors.

Is hotter always smaller? Evolutionary response of Daphnia to global warming. (52469)

Marcin Dziuba, Slawek Cerbin, Lukasz Wejnerowski.

Adam Mickiewicz University.

Daphnia will undergo strong alterations due to climatic changes. One of the threats for
freshwater herbivores like Daphnia is temperature-mediated prevalence of filamentous
cyanobacteria with more frequent and longer blooming events. Cyanobacterial filaments pose
a great threat to this key-stone herbivore. According to hotter is smaller rule, global warming
should reduce the average size of Daphnia, which is advantageous in the presence of
filaments. We hypothesized that under simulated global warming conditions Daphnia will be
smaller; the size reduction should be advantageous in coping with cyanobacterial filaments. In
order to verify our hypotheses we conducted life-history experiments, where Daphnia clones
from artificially heated lakes and closely spaced non-heated lakes were exposed to
filamentous Cylindrospermopsis raciborskii. Our research provided an evidence for a
possibility of evolutionary adaptations to prevalence of filamentous cyanobacteria. Daphnia
from heated lakes differed in life strategy – under the pressure of the filaments they grow
bigger in order to produce more offspring with the cost of shorter life span. This is in conflict
with Hotter is smaller rule, but for organisms, which brood size is limited by body size it is
advantageous to grow larger when they pay cost of shorter lifespan.
Research funded by MNiSW no. DI2012014242

Simulating predicted environmental changes in freshwater ecosystems: how do altered conditions affect Daphnia populations and host-parasite interactions? (52530)

Manja Saebelfeld, Jörg Sareyka, Laëtitia Minguez, Mark O. Gessner, Justyna Wolinska.

Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), (Berlin, DE); Berlin
Institute of Technology (TU Berlin), Berlin, Germany; Freie Universität Berlin (FU Berlin),
Berlin, Germany.

Changes in climatic conditions have been recorded at a global scale over the past decades and are expected to continue in the future. Direct consequences for lake ecosystems include altered thermal stratification, nutrient availability, organic matter turnover and oxygen concentration. This can massively affect primary production and thus have great impact on food web interactions and biodiversity. Another effect of climate change comprises shifts in the disease prevalence within populations since host susceptibility and parasite infectivity are often sensitive to environmental variation. To study effects of climate change on freshwater communities we will use the zooplankter Daphnia and their microparasites as a model system. Our main objectives are to assess effects of predicted global stressors on (i) the intra- and interspecific diversity of Daphnia populations and (ii) the spread of infectious diseases. Thus, laboratory and large-scale field experiments in enclosures will be conducted. The enclosure experiments will be conducted in a unique mesocosm system (LakeLab) consisting of 24 experimental units (1270 m3 each) located in Lake Stechlin (Germany). From this, conclusions could be made on how an ongoing climate change will affect biodiversity and trophic cascades in lakes.

The Great American Biotic Interchange: studying biological invasions in deep time (52558)

Juan D. Carrillo, Carlos Jaramillo, Marcelo R. Sánchez-Villagra.

Paleontological Institute and Museum - University of Zurich; Smithsonian Tropical Research Institute.

During most of the Cenozoic, South America (SA) was an island continent with an endemic mammalian fauna. This isolation ceased during the late Neogene after the formation of the Isthmus of Panama and the establishment of a land connection with North America (NA). As
result, one of the greatest biological experiments of biota exchange at a continental scale took place, the Great American Biotic Interchange (GABI). The GABI begins during the late Miocene (~10–7Ma), the number of GABI participants rapidly increases after ~5Ma and this trend continues during the Pleistocene. We investigate biogeographic patterns in South America when the first immigrants are recorded and we review the temporal and geographical distribution of fossil mammals during the GABI. We support a differentiation between tropical and temperate mammal faunas in SA at least since the middle Miocene. The GABI can be used as a model to study biological invasions at a continental scale and geologic time. The fossil record and the distribution of extant mammals suggest that mammals with NA origin dominate in temperate zones whereas mammals with SA origin dominate in the tropics supporting a strong niche conservatism of temperate and tropical mammals in the continent.

# Phylogenomics method for ranking populations of the endangered Anadromous Atlantic Salmon (Salmo salar) for conservation management. (52577)

Laurelene Faye, Arne Mooers.

SFU.

In an Age of Extinction, wildlife managers need tools to help conserve and manage genetic resources for the future. Wild Atlantic salmon (Salmo salar) is at risk across its range, and so genetic prioritization would seem prudent. Recently, Volkmann and his colleagues developed a new tool allowing the ranking of populations by conservation importance, integrating phylogenomic and environmental data. This state of the art approach is to build phylogenetic networks and score each population by its relative distinctiveness or evolutionary isolation. In a first time, we will simulate dynamic metapopulations using QuantiNemo software in order to identify which indices of genetic distance are most robust for prioritizing populations for conservation for a widely distributed stream species under different management scenarios. Then, using collected S. salar genomic-scale SNP and microsatellite data we will test this tool and construct the phylogenetic network of 50 populations representing all the legally designated at-risk Designatable Units (DUs) in Canada. We hypothesize that some populations may be currently under-evaluated regarding their contribution to present and future S. salar genetic diversities. Such populations might be prioritized both for more active research into the genetic basis of local adaptation, and for conservation by managers, immediately.

# Why would a hybrid clone outcompete its parental species? (Daphnia galeata × longispina species complex) (52581)

Johanna Griebel, Sabine Giessler, Monika Poxleitner, Amanda Navas Faria, Mingo Yin, **Justyna Wolinska**.
Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB); Ludwig-Maximilian-
University Munich, Germany; School of Life Science, Fudan University, China; Free
University, Berlin, Germany.

In natural communities of cyclical parthenogens, rapid response to environmental change is
enabled by switching between two reproduction modes. While long periods of asexual
reproduction allow some clones to outcompete others, sexual reproduction restores genetic
variation in such systems. Moreover, sexual reproduction may result in the formation of
interspecific hybrids. We observed that the Daphnia community of a small lake was
consistently dominated by a single D. galeata × D. longispina hybrid clone. Furthermore, in
artificial communities consisting of many clones (parental species and hybrids), this special
hybrid clone took over within about ten generations. Neither the fitness assay conducted
under different temperatures, and under crowded and non-crowded environments, nor the
carrying capacity test revealed any outstanding life history parameters of this hybrid clone.
However, under simulated winter conditions, the hybrid clone eventually showed a higher
survival probability and higher fecundity compared to parental species. Enhanced
overwintering possibilities as parthenogenetic lineages might explain the successful
establishment of hybrids in the natural community within the D. longispina complex. In
extreme cases, a superior hybrid genotype might be the only remaining clone after cold
winters. Novel traits, such as enhanced overwintering, might promote establishment of
hybrids in nature.

Genetic variability in the wild is influenced by microhabitat characteristics in
Drosophila subobscura (52599)

**Zorana Kurbalija Novicic**, Marija Savic Veselinovic, Bojan Kenig, Aleksandra Patenkovic, Mihailo Jelic, Marina Stamenkovic-Radak, Marko Andjelkovic.

Institute for Biological Research, University of Belgrade, Serbia; Faculty of Biology, University of Belgrade, Serbia; Serbian Academy of Sciences and Arts, Belgrade, Serbia.

While it is predicted that many populations are able to shift their geographic ranges to track
global change, the question remains of the potential of populations to adapt to rapid change in
their microhabitats. The aim of the present research is to understand the microevolutionary
processes across natural populations and to detect the actual degree of local adaptation
through the dynamic interaction between selective pressures and gene flow. The research
consists of two levels: i) assessing genetic diversity of natural populations of Drosophila
subobscura inversion polymorphism, mtDNA variability and microsatellites, ii) assessing the
habitat diversity by defining the microclimatic conditions of each selected habitat across
several environmental parameters across small geographic scale. Results showed that
populations of this species are genetically diverse, even on a small geographical scale.
Different chromosomal gene arrangements have been found to be differently favored in
various microhabitats. The results of this study will provide the additional information about
the adaptive character of inversion polymorphism, and help us answer questions about the
evolutionary potential of the populations in the wild.
# Evolutionary history counts in population response to thermal stress in inbred and outbred lines of Drosophila subobscura (52604)

**Aleksandra Patenković**, Marija Tanasković, Zorana Kurbalija Novičić, Bojan Kenig, Marina Stamenković-Radak, Marko Andělković.

*Institute for Biological Research "Siniša Stanković"; Faculty of Biology, University of Belgrade, Belgrade, Serbia; Serbian Academy of Sciences and Arts, Belgrade, Serbia.*

Ongoing climate change and landscape alterations represent a serious threat for existence of many species. Temperature, one of the most important factors with large influence on biological processes, can act synergistically with genomic stress, leading to significant decrease of fitness and deterioration of population survival especially in isolated populations challenged with habitat fragmentation. Therefore, the consequences of temperature stress on population level must be studied in combination with genomic stress.

We analyzed wing size and shape of inbred and outbred lines of Drosophila subobscura from two ecologically different habitats, reared under 16°C and 22°C temperature. The results showed statistically significant difference in wing size between homozygote and heterozygote groups, with both cold and heat thermal treatments decreasing wing size. Statistically significant difference between heterozygote groups may be contributed to maternal effect. Differences in a capacities of populations to adapt to thermal stress, reflects different population histories that these populations have experienced: one in polluted urban part of Belgrade under anthropogenic influence, other in natural unpolluted resort with stable microclimatic conditions.

The obtained results suggest that for predicting the consequences of environmental changes, it is necessary to take into account the population history, as well as the degree of genomic stress.

# Spatial distributions of genetic diversity and local adaptation in metapopulations on heterogeneous landscapes (52834)

**Etsuko Nonaka.**

*Metapopulation Research Group, Department of Biosciences, University of Helsinki.*

Existing theories of population genetics for spatially subdivided populations often assume a constant genetic variance across local populations for mathematical tractability. Genetic diversity is a key ingredient determining evolutionary potential of populations, especially under changing environments. It can be temporally and spatially variable and influenced by selection, gene flow, and genetic drift. In heterogeneous landscapes, spatial habitat structure influences such evolutionary as well as demographic processes and determines gene flow and the prevalence of genetic drift, resulting in heterogeneous spatial distributions of genetic
diversity. We developed an eco-evolutionary model of a metapopulation living in a heterogeneous landscape to investigate 1) the effects of dynamic vs. constant genetic diversity on local adaptation, and 2) how landscape structure may affect the spatial distributions of genetic diversity. The results suggest that dynamic genetic diversity can produce different patterns of local adaptation than when it is kept constant at the mean value. Long-term averages of genetic diversity and the degree of local adaptation can be well predicted by population size and types of immigrants, which are in turn predicted largely by patch area and connectivity. Frequent extinction and colonization events can obscure this relationship.

## Evolutionary trade-off in thermal adaptation and its effect on responses of animals to global climate change (52936)

Karin Maldonado, Natalia Lopez-Morgado, Gabriela Piriz, Francisco Bozinovic, Pablo Sabat.

Departamento de Ciencias Ecológicas, Universidad de Chile; Departamento de Ecología, LINC-Global, CAPES, Pontificia Universidad Católica de Chile.

The effect of global warming on species' geographic ranges has attracted much attention and concern from researchers in recent decades. In this sense, it has suggested that limits of animals' distribution may be set according to their physiological tolerance or phenotypic plasticity in response to climate. Nevertheless, it has proposed that species that evolved greatest physiological tolerances have done so at the expense of tolerance's phenotypic plasticity. Such evolutionary trade-off in thermal adaptation, may cause that extant more thermo tolerant species would paradoxically be most likely to be at threat by increasing temperatures. Due to thermal tolerances and metabolic rates are strongly influenced by environmental temperatures and linked to species' geographic distribution, those variables have been widely used to study the effect of global change. In the present study, we examined thermal tolerances (CTmin, CTmax) and metabolic scopes (BMR, Msum), together with their acclimatory capacities, in rodents (Phyllotis darwini) from the northernmost and the southernmost limit of their distribution in Chile. We found a significant relationship between physiological tolerance and phenotypic plasticity; however, this pattern differed in relation to the trait analyzed. The results suggest that more studies are needed to establish generalizations about the existence of an evolutionary trade-off on thermal adaptation.

## Niche conservatism and evolutionary range expansion in mycalesine satyrine butterflies (52987)

David Lees, Erik van Bergen, Kwaku Aduse-Poku, Brattström Oskar.

Cambridge University.
A spectacular Old World radiation of mycalesine butterflies resulted in largely monophyletic radiations in major tropical biogeographic regions, each of 70+ species. A robust phylogeny and distribution records across Mycalesina allows us to compare niche models between regions, both at species and higher clade level, examining the extent that phylogenetic niche conservatism (PNC) may constrain climatically realized niches. In African Bicyclus for example, nested sets of early diverging lineages are relatively restricted to W.African rainforests as expected under PNC, whereas in more distal parts of the evolutionary radiation, dramatic expansion occurred into savannah environments, likely driven by Miocene climatic change favouring adaptation to a C4 photosynthetic pathway in their grass hostplants. This contrasts to the genus Heteropsis in Madagascar, where radiations have largely occurred within humid forest regions, and early diverging lineages are widespread. Projecting the fundamental niches using surfaces at the same spatial scale confirms clearcut differences within the Afrotropics. These models help to understand the varying extent to which a process of sequential colonization of land masses and archipelagos may have happened with, or been limited by, PNC. Present inference illuminates the potential of range expansion or contraction for future climate scenarios, including predicted movements along latitudinal/elevational gradients.

Plenary MON MAX 350/351

# The genomic basis of sexual dimorphism (53360)

**Judith Mank.**

*University College London.*

Sexual dimorphism is arguably the most pervasive form of intra-specific diversity in the animal kingdom, and the prevalence of sexual dimorphism in animals prompted Darwin's conjecture of sexual selection as a force distinct from natural selection. Central to the study of sexual dimorphism is the question of how divergence occurs between the sexes within a species when so much of the genome is shared. In many cases, phenotypic sex differences are the result of transcriptional dimorphism, and integrating genome and transcriptome data offers a powerful tool for understanding the evolution of sexual dimorphism. I'll discuss recent studies testing the relationship between sex-specific selection and phenotypic sexual dimorphism with genome and transcriptome evolution. These studies reveal the ways that selection navigates evolutionary constraints and sexual conflicts to create both inter- and intra-sexual phenotypic diversity. These observations and approaches are also valuable for understanding many other forms of intra-specific phenotypic variation.

Plenary TUE MAX 350/351

# Dissecting the evolutionary ecology of reproductive strategies in the wild
(53363)

**Jane Reid.**
Reproductive strategies enacted by individual organisms define social interactions and influence allele and genotype frequencies in subsequent generations, and thereby shape the course of evolution. However, evolutionary ecologists still do not fully understand the evolution or persistence of widespread reproductive strategies, including biparental inbreeding and multiple mating. Progress remains limited because reproductive strategies and fitness have not been comprehensively measured in wild populations experiencing natural social and environmental variation. Furthermore, field studies typically estimate phenotypic associations between reproductive strategy and fitness components rather than directly estimating key genetic (co)variances that could drive or constrain evolution. I applied quantitative genetic analyses to comprehensive pedigree, reproductive strategy and fitness data from socially monogamous but genetically promiscuous song sparrows (Melospiza melodia), to estimate genetic (co)variances that could underlie micro-evolution of extra-pair reproduction and inbreeding. Analyses revealed substantial additive genetic variance in the degrees of extra-pair reproduction expressed by females and males, with divergent negative and positive genetic covariances with fitness components. The degree of biparental inbreeding also showed substantial additive genetic variance, but sex-specific selection was weak despite inbreeding depression in offspring fitness. These analyses provide new insights into evolution of reproductive strategies, and illustrate explicit test of key evolutionary hypotheses in nature.

# Social evolution in microbes: from model systems to the microbiome (53520)

**Kevin Foster.**

Since Darwin, evolutionary biologists have been fascinated by cooperative behaviour. Honeybee workers labour their whole life without reproducing, birds make alarm calls, and humans often help each other. Much less attention has been paid to the microbes. They exist all around us and inside us, and it has become clear that microbes commonly live in densely interacting communities that have major effects on animals and plants. But what determines if microbes are cooperative towards each other and their hosts? We study this question by combining theory with experimental systems, including pathogenic bacteria, budding yeast and the mammalian microbiome. We find that single-genotype patches naturally emerge in microbial communities, which favours strong cooperation by kin selection. By contrast, interactions between genotypes can be strongly competitive. Bacteria strains are often at war and we find that they can rapidly detect incoming attacks and respond in kind. Microbial interactions then follow the same evolutionary principles that were first understood through the study of animal behavior. However, one unusual and fascinating property of microbes is that an entire ecosystem can lie within another evolving organism: a host. This raises the possibility that hosts will act as ecosystem engineers that change the rules of microbial interaction for their own benefit.
# How do proteins evolve? (53508)

**Dan Tawfik.**

*Weizmann Institute of Science.*

New proteins evolve via genetic processes of duplication and diversification. We investigate the mechanisms, driving forces and intermediates that underlie these processes, thus giving rise to new proteins, with new structures and functions.

I will describe two recent, unpublished studies:

* Coevolution of transcriptional and protein regulation. Duplication, giving rise to paralog genes, is the most common mechanism for evolutionary innovation. The divergence of transcriptional regulation of paralogs is routinely recorded. However, no evolutionary trait evolves on its own. I will show a case study, indicating why and how promoters and the proteins whose transcription they drive coevolve.

* The birth of a new protein. Alongside paralogs, orphan genes comprise more than a third of all genomes. But is the 'birth' of a new, globular, structured protein a feasible event? We reconstructed in the laboratory the de novo emergence of a functional, globular protein by cooption of a short sequence motif from an existing protein belonging to a different fold. Folding efficiency, or foldability, and not the stability or function of the native state, was the key parameter under evolutionary selection.

# Digging for genes that affect behavior (53507)

**Hopi Hoekstra.**

Understanding which genes affect fitness-related behaviors, and how they work in the brain, remains a major challenge in biology. To address this goal, we are capitalizing on natural variation in behavior within and between species of deer mice (genus Peromyscus). In this talk, I will focus on an innate behavior – burrowing, an intriguing and complex animal architecture – to explore the genetics and neurobiology of behavioral evolution.

# Supergenes, sex and sociality (53608)

**Laurent Keller.**

*department of ecology and evolution.*

Understanding the genetic basis of evolutionary adaptations is a central focus of modern evolutionary biology. Recent studies have uncovered a panoply of complex phenotypes,
including locally adapted ecotypes and cryptic morphs, divergent social behaviours in birds and insects, as well as alternative metabolic pathways in plants and fungi. In this talk I will show how the occurrence of such adaptive alternative phenotypes can be generated and maintained by either phenotypic plasticity or supergenes (i.e., clusters of tightly linked loci). I will in particular discuss the case of alternative forms of social organization being controlled by social chromosomes having similar properties as sex chromosomes.

# The Time-Scale Of Recombination Rate Evolution In Great Apes (53364)

**Laurie Stevison**, August Woerner, Jeffrey Kidd, Joanna Kelley, Krishna Veeramah, Kimberly McManus, Great Ape Genome Project, Carlos Bustamante, Michael Hammer, Jeffrey Wall.

*University of California San Francisco.*

We recently completed three linkage-disequilibrium (LD)-based recombination maps generated using whole-genome sequencing of 10 Nigerian chimpanzees, 13 bonobos, and 15 western gorillas, collected as part of the Great Ape Genome Project (Prado-Martinez et al. 2013). We also identified species-specific recombination hotspots in each group using a modified LDhot framework, which greatly improves statistical power to detect hotspots at varying strengths. Using species-specific PRDM9 sequences to predict potential binding sites in hotspot regions as compared to match cold spot regions, we identified an important role for PRDM9 in predicting recombination rate variation in multiple great ape species. While previous research showed that PRDM9 is not associated with recombination in western chimpanzees (Auton et al. 2012), we attribute this lack of signal to higher population-level diversity at the PRDM9 locus in this group. Additionally, we show that fewer hotspots are shared among chimpanzee subspecies than within human populations, further narrowing the time-scale of complete hotspot turnover. We quantified the variation in the biased distribution of recombination rates towards recombination hotspots across great apes, highlighting similar distributions across great apes with Europeans as an outlier. Further, we found that pairwise comparisons of broad-scale recombination rates decay more rapidly than pairwise nucleotide divergence between species. We also compared the skew of recombination rates at centromeres and telomeres between species and show a skew from chromosome means extending as far as 10-15 Mb from chromosome ends. Our study is the first to analyze within- and between-species genome-wide recombination rate variation in several close relatives.

# Mathematical adventures in sex and disease evolution (53375)

**Matthew Hartfield.**

*University of Toronto.*