There are several examples of plant pathogens adapting to their hosts, but very little evidence of hosts evolving resistance under the pressure of pathogen attack. The diverse resistance structure detected within host populations suggests that natural plant populations have the capacity to evolve in an adaptive manner in response to pathogen attack. One of the key challenges in disease biology is to understand when and where disease resistance evolves, and what the consequences are for epidemiological dynamics

The aim of this study is to determine how the resistance structure is distributed within Plantago lanceolata populations in Åland islands. The obligate parasite Podosphaera plantaginis infects small proportion of the populations each year. An earlier study has demonstrated that highly connected host populations support higher resistance than isolated host populations, yet the role of pathogen imposed selection on resistance evolution remains unclear. This study consists highly and poorly connected host populations with different disease history. Variability in resistance has been tested in a large inoculation experiment using sympatric and allopatric mildew strains. The obtained results from inoculation experiments linked to epidemiological data will help us to understand how host population evolutionary potential changes with degree of population connectivity and past selection intensity.

Poster session B - GEN 2000

# Genomic insights into the evolution of Borrelia resistance along altitudinal gradients in the Alps (51774)

**Luca Cornetti, Mélissa Lemoine, Barbara Tschirren.**

*Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Switzerland.*

Lyme borreliosis is a prevalent zoonotic disease in Europe, having major debilitating effects in humans. It is caused by the spirochete Borrelia sp., which is transmitted by ticks to animal hosts, in particular small rodents. Natural hosts, such as bank voles (Myodes glareolus), are commonly infested with ticks throughout their life. However, only about 20-30% of the animals become Borrelia-infected, demonstrating that natural hosts have evolved powerful defence mechanisms, which prevent and/or control Borrelia infection. To date, this variation in Borrelia resistance remains poorly understood.

Recent temperature increases in the Alps allowed the pathogen to colonize altitudes that were previously Borrelia-free. This natural experiment provides a unique opportunity to investigate resistance evolution in newly exposed host populations, providing a powerful model to study rapid evolutionary changes in response to emerging pathogens. Using a combination of RADsequencing and candidate gene approaches, we compare genomic variation in rodent populations with a long co-evolutionary history with Borrelia, rodent populations that are newly exposed to Borrelia, and populations that are still Borrelia-free. This combination of top-down and bottom-up approaches allows us to gain novel insights into the role of parasites in shaping immune gene evolution in the wild.
## Genetic consequences of an extraordinary lifestyle (51866)

Anne Andersen, David Richard Nash.

*Centre for Social Evolution, University of Copenhagen.*

Antagonistic coevolution caused by strong selective pressures has been shown to play an important role in the maintenance of genetic diversity in natural populations. The socially parasitic butterfly Maculinea arion experiences strong selective pressures from its host ants. The caterpillars are adopted by ant workers and stay in the ant nest all winter, feeding on the ant larvae. The caterpillars have high, but variable, mortalities before and after their adoption by ants, and only a tiny fraction of eggs will survive to adulthood. The species might thus experiences genetic bottlenecks in every generation. All Swedish populations of the species have low effective population sizes and show signs of recent genetic bottlenecks even in large, stable populations. The low effective population sizes are expected to increase genetic drift, causing rapid genetic differentiation and high temporal turnover in allele frequencies within populations. This suggests that the extraordinary phyto-predacious lifestyle of M. arion leads to inherently low but rather constant genetic diversity. We tested this hypothesis in a contemporary Swedish population using neutral genetic markers.

Poster session B - GEN 2000

## "Mycobacterium ulcerans dynamics and virulence strongly depend on chitin concentration in the environment" (51931)

Daniel Sanhueza.

*Institute de recherche et developpement.*

M. ulcerans is the causative agent responsible for the devastating skin infection Buruli ulcer, which is prevalent in many tropical countries, notably in western and central Africa. The incidences of the disease are significantly higher on floodplains and where there is an increase of human aquatic activities. Despite this, our understanding of the disease remains limited. With the purpose to elucidate this lack of knowledge, in the laboratory M. ulcerans was cultured into different abiotic conditions measured in French Guiana and Cameroun. In our research we are interested to test if these abiotic factors have an effect in the development and genetic expression of M. ulcerans.

Our results show for the first time that the presence of chitin has a significant effect on the growth and genetic expression of M. ulcerans.

One of the hypotheses of transmission of this disease proposes aquatic insects as vectors, transmitting the infection to humans by biting. Our results suggest that the chitin presents in the cuticle of these insects helps developing the mycobacterium in nature. Moreover M. ulcerans possesses an enzyme chitinase, so its possible that chitin is not just an environmental support for M. ulcerans, but also could be a source of nutriment.

Poster session B - GEN 2000
# Priority effect in the competition between the intracellular pathogens Nosema apis and Nosema ceranae in the midgut of the honey bee (Apis mellifera) (51943)

**Myrsini Natsopoulou**, Dino McMahon, Vincent Doublet, John Bryden, Robert Paxton.

Martin Luther University; Queen's University Belfast; Freie University Berlin; German Centre for Integrative Biodiversity Research (iDiv); Royal Holloway, University of London.

Both humans and animals are exposed to a wide range of parasite species; harbouring more than two species at the same time is quite frequently observed in nature. Yet the epidemiological and ecological processes determining the outcome of mixed infections are poorly understood. We explore multiple parasite interactions within a single species host, focusing on the western honey bee (Apis mellifera) and the two Microsporidia species that infect it, one exotic (Nosema ceranae) and one coevolved (Nosema apis). We evaluated the outcome of mixed infections by comparing pathogen growth in single vs double infections given simultaneously vs sequentially. We demonstrate that parasite growth depends on order of infection, with the exotic species being a better competitor than the native one. To investigate further the implications of this asymmetric interspecific competition on the rapid emergence of *N. ceranae* as a global disease threat to honey bees, we use a mathematical model of disease prevalence. We find that, incorporating the asymmetric competition observed in our lab experiment into the model, we were able to capture the observed patterns of prevalence of these two pathogens in nature. Our findings demonstrate that knowledge of complex multi-species interaction is critical to understand host-parasite community structure.

Poster session B - GEN 2000

# Does recombination accelerate adaptation of RNA viruses to a local host? (52072)

**Vincent Doublet**, Dino P. McMahon, Andreas Gogol-Döring, Myrsini E. Natsopoulou, Silvio Weging, Robert J. Paxton.

German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany; Institute for Biology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany; School of Biological Sciences, Queen's University Belfast, UK; Institute of Biology, Freie Universität, Berlin, Germany; BAM Federal Institute for Materials Research and Testing, Berlin, Germany.

RNA viruses have amongst the highest recombination rates in nature. The role of recombination in adaptation to a host is, however, debatable as recombination can combine mutations into one genome, regardless of whether they are advantageous or deleterious. In the honeybee (Apis mellifera), two RNA viruses from the same virus complex, Deformed wing virus (DWV) and Varroa destructor virus (VDV), are known to recombine in nature. To test whether recombination is involved in adaptation to a local host, we first co-inoculated DWV and VDV in naïve experimental honeybees. After deep-sequencing of the ancestral inoculates and the viral population in co-infected honeybees (one week post-infection), we found that recombination was extensive and occurred across the entire length of the viral genome, and
more specifically at regions of high sequence similarity. Infections with both viruses were as virulent as infection by VDV alone, but we did not detect predominance of any particular recombinant sequence. We hypothesize that recombination could enable rapid virus adaptation to novel host environments. We aim to test whether one or more recombinants can be evolved experimentally under controlled conditions, and ask whether these are linked to selectively advantageous differences and may accelerate adaptation to new hosts.

Poster session B - GEN 2000

# Immature larvae of the eyefluke Diplostomum pseudospathaceum enhance anti-predatory behavior of fish: evidence supporting the “predation suppression” hypothesis. (52137)

Mikhail Gopko, Victor N Mikheev, Jouni Taskinen.

A.N. Severtsov Institute of Ecology and Evolution, Moscow, RAS; University of Jyväskylä, Finland.

Tropically-transmitted parasites need time to reach infectivity, when developing in the intermediate host. A theoretical model (Parker et al., 2009) predicts that before full development, parasite larvae should make their hosts less vulnerable to predators (predation suppression hypothesis) to increase probability of surviving until infectivity. However, there is still little evidence of such manipulations by non-infective parasite stages. We studied experimentally the influence of immature metacercariae of the eyefluke, Diplostomum pseudospathaceum, on the anti-predator behaviour of the young-of-the-year rainbow trout and cyprinids (several species), to test the predation suppression hypothesis. Infected fish harbouring on average 7.7 (range 1-26) larvae, which corresponds to naturally occurring parasite numbers in YOY fish, were significantly less vulnerable to simulated predation (both rainbow trout and cyprinids), less active (rainbow trout) and preferred deeper layers of water (cyprinids) when compared with control fish harbouring no larvae. Our findings suggest that immature larvae of D. pseudospathaceum induce changes in host behavior that can protect them from predation, supporting predation suppression hypothesis and indicating that manipulations of non-infective parasites may play an important role at modulating predator-prey interactions in the natural habitats.

Poster session B - GEN 2000

# Adaptation of a holoparasitic plant to new hosts – genetic differentiation or phenotypic plasticity? (52195)

Bojana Stojanova, Philippe Simier.

LBPV LUNAM Université de Nantes.

Phelipanche ramosa is a holoparasitic plant of the Orobanchaceae family. Contrary to most of the species in this family, its lifecycle follows that of an annual weed, allowing its spread
among a large range of cultivated crops. The genetic diversity of this species has not been extensively studied, though it could help the understanding of evolutionary mechanisms underlying adaptation to novel hosts, such as the one recently observed on rape in western France. We genotyped over 60 populations of P. ramosa coming from different geographical regions and three main host plants in France (rape, hemp, tobacco) using 22 SSR markers. AMOVA and PCA analysis show low intrapopulation variation and high and significant inter population genetic variation that seems to be influenced by geographic origins and host plants to different extents. In Western France, populations found on rape, hemp and tobacco are all genetically very distant whereas in eastern France the hemp type from west is found on both hemp and rape. We will further test these genotypes on a range of hosts in a growth chamber to clarify to what extent do genetic differentiation and phenotypic plasticity influence the adaptation of P. ramosa to different hosts on different geographic scales.

# A new method to analyze the dynamics of multivariate distribution of fitness traits in large asexual populations: application to the evolution of virulence-transmission trade-off (52244)

Yoann Anciaux

ISEM.

Modelling the dynamics of pathogen adaptation implies following the evolutionary dynamics of several fitness traits (virulence, transmission etc.) with a typically complex genetic basis (many alleles, epistasis). Furthermore, these dynamics are often coupled with the demographic dynamics and evolution of the host. Such processes often become analytically intractable.

Here, we explore the use of an analytical tool to model the dynamics of the full multivariate distribution of fitness traits in large asexual populations, through their generating function. This allows following the effect of selection among many co-segregating types and of background-dependent mutation effects (epistasis).

We will study the insights obtained from this approach in a model where virulence and transmission are distinct optimizing functions of a set of underlying phenotypes. We will consider adaptation from standing variance alone, and the impact of de novo mutations. Within our framework, the virulence-transmission trade-off is allowed to evolve and the host's demographic feedback explicitly enters the dynamics of parasite evolution.

# Variation of life history traits of nematode parasites in undisturbed habitats of Serbia (52270)

Vladimir M. Jovanović, Ivana Budinski, Borislav Čabrilo, Tanja Adnađević, Olivera Bjelić-Čabrilo, Jelena Blagojević, Mladen Vujošević.
Varying climatic conditions can impose constraints on life history of both hosts, and parasites.
We studied variation of parasite life history traits (sex ratios, extent of the sexual size
dimorphism and fecundity) as a result of local adaptations to climatic conditions, host age and
genetic background. For the object of research, we chose four parasitic nematodes of a single
host species, yellow-necked field mouse (Apodemus flavicollis), known for the common
presence of B chromosomes in individual genotypes. The B chromosomes were previously
shown to influence the interaction of this species with some parasitic nematodes, together
with standard genes included in adaptive immune response. We analysed parasites of 136 host
individuals from 14 localities in Serbia. Variation in parasite infrapopulation sex ratios was
correlated with the habitat temperature factors in two nematode species, despite the life cycle
differences between them. For only one parasite species, the range of fecundity could be
explained by climatic factors. Host-related factors (age and the presence of B chromosomes)
partially explained observed variation in studied life history traits of parasites. Further studies
of parasite life history traits in the undisturbed habitats are needed in order to draw more
decisive conclusions.

Fine-tuned, context-specific manipulation of an intermediate crustacean host
by its acanthocephalan parasite (52289)

Timo Thünken, Theo C. M. Bakker, Sebastian A. Baldauf.

Parasites with a complex life cycle are supposed to influence the behaviour of their
intermediate host in such a way that the transmission to the final host is enhanced, but reduced
to non-hosts. Here, we examined whether the trophically transmitted acanthocephalan bird
parasite Polymorphus minutus adaptively alters the anti-predator behaviour of its intermediate
host, the freshwater amphipod Gammarus pulex. Uninfected gammarids showed negative
phototaxis, whereas infected ones were photophilic indicating that the parasite manipulates
the phototactic responses of its intermediate host thereby increasing the probability of
ingestion by final bird hosts. In response to specific non-host predatory cues (fish cues in our
study) infected gammarids showed stronger anti-predator behaviour than uninfected ones
suggesting that the bird parasite manipulates anti-predator behaviour of its intermediate host
to reduce the probability of transmission to dead-end hosts. When phototaxis and fish
avoidance were jointly examined, uninfected gammarids showed increased photophobia
suggesting that both factors act additively. Interestingly, P. minutus infected gammarids
showed photophobia in this context as well suggesting fine-tuned context-dependent parasitic
manipulation.
# When parasites disagree: Interspecific conflict over host manipulation (52341)

**Nina Hafer**, Manfred Milinski.

*MPI for evolutionary biology.*

Host manipulation is a common strategy by which parasites alter host behavior to enhance their own fitness. In nature, hosts are usually infected by multiple parasites with potentially conflicting interests with regards to their host's behavior. This can lead to a conflict over host manipulation. Experimental studies of such a conflict including parasites from different species are lacking. The cestode Schistocephalus solidus and the nematode Camallanus lacustris both use copepods as their first intermediate host. They need to spend some time inside this host before they are ready to be trophically transmitted to their subsequent fish host. Accordingly, not yet-infective parasites lower host activity to reduce fatal premature predation. Infective ones increase host activity to enhance predation to continue their life cycle. We experimentally infected lab-bred copepods such that they harboured either an infective S. solidus and a not yet-infective C. lacustris or vice versa. Such an interspecific conflict can, as we found, lead to a compromise between the manipulation effects each parasite would achieve when alone. This result differs from pure S. solidus infections in which the infective parasite completely sabotages the manipulation effect by the not yet-infective one. These and further results will be presented.

Poster session B - GEN 2000

# Experimental evolution of the spider mite, Tetranychus urticae, on tomato plants: which traits matter in adaptation to a novel host? (52421)

**Cassandra Marinosci**, Ophélie Ronce, Sara Magalhães, Isabelle Olivieri.

Université Montpellier 2, Institut des Sciences de l'Evolution, UMR5554, Place Eugène Bataillon, 340; CBA Centro de Biologia Ambinental, Faculdade de Ciências da Universidade de Lisboa, Edificio C2, 3º.

Plants and herbivores exert strong selection upon each other, resulting in a coevolutionary arms race. In fact, plants evolve wide physical and chemical defences in response to attacks by herbivores. Conversely, herbivores develop mechanisms to cope with these plant defences. This diversifying and recurring antagonistic coevolution is particularly relevant for polyphagous species that experienced a diversity of host plants with a large range of systemic defences. The present study describes adaptation to a new host plant. By using experimental evolution with a spider mite species, Tetranychus urticae, we addressed the following questions: are populations evolving previously on tomato plants more adapted to this host plant relative to ancestral populations (evolving on bean plants)? In this case, is this adaptation due to the capacity of these populations to inhibit or resist to plant defences? This work underlines the diversity of responses of pest herbivores to host plant defences and shows that a variety of strategies are used by spider mites to respond to shift in host plant.
# Pathogen emergence and evolution in a network of wild living house mice.
(52447)

**Jonas Ismael Liechti**, Martin Mueller, Gabriel Etan Leventhal, Barbara Koenig, Sebastian Bonhoeffer.

*ETH Zurich; University of Zurich.*

Contact structure heterogeneity has been shown to influence both disease spread[1] and pathogen evolution[2] in simulated epidemics. The relative importance of such contact heterogeneity for the epidemiology of real host-pathogen systems has remained unclear due to the technical challenges of observing real host contact networks in wild populations. Furthermore, these models assume static networks where contacts between individuals exists for the whole duration of an epidemic. Here, we present results on the spread and evolution of a model pathogen in a population whose dynamic contact pattern has been parametrized based on data of wild house mice for which interactions between individuals have been monitored for several years. The resolution of the data is high such that we can construct a detailed temporal contact network of the host population. This allows us to study the spread and evolution of pathogens in a biologically relevant contact network.

[1] J. Lloyd-Smith et al., Nature, 438:355-359 (2005)

[2] G. Leventhal, A. Hill et al., Nature Communications, in press

# Multiple infections in the anther smut fungus Microbotryum (52485)

**Taiadjana Fortuna**, Michael E. Hood, Manuela Lopez-Villavicencio, Hélène Badouin, Alodie Snirc, Stéphanie Le Prieur, Christian Raquin, Jacqui Shykoff, Tatiana Giraud.

*Université Paris-Sud, CNRS, Dept. Écologie, Systématique et Évolution, Orsay, France; Amherst College, Department of Biology, Amherst, Massachusetts, USA; Muséum National d'Histoire Naturelle, Dept. Systématique et Évolution, Paris, France.*

Theory predicts that virulence should be higher when multiple strains of parasites regularly compete within hosts. This is because, under conditions of multiple infections, parasites that rapidly exhaust limiting host resources produce more offspring than those following a prudent strategy. Conversely, virulence can be reduced in hosts with multiple infections if competitors inhibit one another. We study multiple infections in Microbotryum phytopathogenic fungi, responsible for the anther smut disease in Caryophyllaceae plants. Previous studies have shown that multiple infections of M. lychnidis-dioicae occur frequently in natural populations of Silene latifolia. Competitive inhibition and exclusion occur between unrelated strains within the infected plant, i.e. pathogen relatedness impacts virulence. Here, we assessed the frequency of multiple infections of M. saponariae infecting the plant Saponaria officinalis in natural populations, and we studied the mechanism of competitive exclusion and inhibition. Hyphae of M. saponariae can indeed grow in vitro allowing observation of fungal hyphae interactions. New microsatellite markers have been developed to identify fungal genotypes of
M. saponariae. Controlled inoculations have also been carried out in the greenhouse to investigate how parasite fungal genotypes interact within plants and the effects of multiple infections and pathogen relatedness on infection success and virulence.

# Are parasitoids locally adapted to their hosts' endosymbionts? (52507)

Christoph Vorburger, Romain Rouchet, Luis Cayetano.

ETH Zürich & Eawag; Academy of Sciences of the Czech Republic, Brno; UC Berkeley, USA.

Many organisms rely on 'helpers' in the form of microbial endosymbionts for defence against parasites. Aphids enjoy increased resistance to parasitoids when infected with the facultative bacterial symbiont Hamiltonella defensa, which reduces parasitism in the field and thus hampers biological control of pest aphids. Parasitoids, on the other hand, have the capacity to adapt to the presence of defensive symbionts in their host, as shown by experimental evolution in the lab. This suggests that parasitoids may be locally adapted to the prevalence of defensive symbionts in their host populations. Across 17 populations of the aphid parasitoid Lysiphlebus fabarum, we do indeed see a positive association between their ability to parasitize Hamiltonella-protected aphids and the local prevalence of this symbiont, but this correlation is weak and non-significant. An assessment of intraspecific variation in both antagonists provided a possible reason for this apparent lack of local adaptation. Different strains of Hamiltonella protect well against some but not against other genotypes of the parasitoid. This genotype-specificity precludes a general adaptation of parasitoids to the defence provided by Hamiltonella. The mechanistic basis of this specificity and whether parasitoids are adapted to the symbiont strains they encounter most frequently are the topic of ongoing research.

# Gyrodactylus salaris transcriptome: functional characterization and analysis in relation to adaptations to parasitism. (52629)

Ksenia Zueva, Tiina Sävilammi, Craig R Primmer.

University of Turku.

Gyrodactylus salaris is a parasitic flatworm that poses a great threat to North Atlantic populations of Atlantic salmon. We studied transcriptome characteristics of G. salaris, in order to better understand the mechanisms and evolution of parasitism. We present a de novo assembly of the parasite transcriptome, approximately one third of which could be functionally annotated using the Gene Ontology, protein families and Kyoto Encyclopedia of Genes and Genomes databases. This annotated sequence collection represents an important genomic resource for G. salaris, and is discussed in the light of suggested genomic adaptations to obligate parasitism in neodermatan flatworms. Based on the recently published
first draft of G. salaris genome such adaptations have been proposed to include reduction or absence of a number of essential genes, among which are genes encoding peroxisomes, heat shock proteins, and proteins in the fatty acid synthesis pathway. Such genes were also absent or reduced in our study. Moreover, the possible reduction of genes in the fatty acid synthesis pathway in G. salaris is in line with our earlier observations of signals of parasite-driven selection in Atlantic salmon genomic regions including fatty acid metabolism genes, thus possibly suggesting genomic co-evolution of host and the parasite.

Poster session B - GEN 2000

# Local differences in parasitism and competition shape defensive investment in a polymorphic eusocial bee (52723)

Christoph Grüter, Lucas von Zuben, Francisca Segers.

University of Lausanne, Switzerland; University of São Paulo, Brazil.

Adaptive colony demography theory predicts that colonies should flexibly adjust the investment in different worker castes depending on the colony needs in a given environment. For example, colonies should invest more in soldiers in a more dangerous environment. However, evidence for this prediction has been mixed. We examined whether defensive investment is adjusted to local ecology in the only known bee with a morphologically distinct soldier caste, Tetragonisca angustula. We studied three populations that differed in the density of food competition and the occurrence of a parasitic robber bee. We found that colonies coexisting with robber bees had on average 45-97% more soldiers defending the nest entrance, while colonies facing stronger foraging competition had c. 7-8% smaller guards. When released from intense competition by colony relocation, body sizes of guards and foragers increased. When we introduced chemical robber bee cues at nest entrances, we found both a short-term and a long-term up-regulation of the number of soldiers defending the colony. Our study supports adaptive colony demography theory and highlights the importance of colony threats and competition as selective forces shaping colony phenotype.

Poster session B - GEN 2000

# A cryptic species in a generalist parasitic wasp (Hymenoptera: Braconidae: Aphidiinae): Host range and reproductive isolation (52750)

Yoann NAVASSE, Manuel PLANTEGENEST, Anne LE RALEC.

Université Rennes 1; Agrocampus Ouest; INRA.

In agroecosystems, specialist or generalist character of natural enemies may have implications in the regulation of pest populations. Insects, such as aphids, can cause major damage to cultivated plants. A group of natural enemies of aphids presents a much higher degree of specialization: parasitoids. However, among the four hundred species composing this Aphidiinae, various degrees of specialization are observed: while most species parasitize only
one or two species of aphids, some species have been recorded on more than twenty different host species. But these generalists species are challenged because recent work suggests that they could include specialized biotypes or cryptic species.

Diaeretiella rapae is the most generalist Aphidiinae, host range including more than sixty aphid species. We used D. rapae to test the hypothesis of structuration of generalist species in several specialized sub-units, possibly being real species. We compared host range of various strains coming from different aphid species and geographic areas by host switching experiments. Then, we tried to assess their taxonomic status by checking their reproductive compatibility.

Our results showed differences in the parasitic success between strains. Moreover, reproductive isolation was detected. D. rapae, known as a generalist species, seems to include more or less specialized entities, some of them being cryptic species.

Poster session B - GEN 2000

## Fast spread of a fungal parasite in ant supercolonies (52762)

Simon Tragust, Heike Feldhaar, Xavier Espadaler, **Jes Søe Pedersen**.

*University of Bayreuth; Autonomous University of Barcelona; University of Copenhagen.*

Many ant species are highly successful invaders and can dominate vast areas by forming dense networks of connected nests in contrast to the smaller and spatially dispersed colonies of most social insects. However, it was recently proposed that such supercolonies are more vulnerable to infection by parasites and diseases as they would serve as large targets with high rates of transmission from nests to nest. Here we studied the invasive garden ant Lasius neglectus, a pest species which is currently spreading throughout Europe where several populations are infected with the ectoparasitic fungus Laboulbenia formicarum. The fungus is also introduced so a new host-parasite relationship is formed. In two populations (supercolonies) we followed the prevalence and intensity of the infection over four to 10 years, revealing independent epizootic spread of the parasite with a 14% annual increase in prevalence until c. 80% of all ants were infected. In contrast, no other local ant species with normal colonies carried the parasite. These results give the first direct support to the hypothesis that supercolonies potentially face an important challenge from parasites and diseases, implying that such ant species are likely to have evolved efficient ways to cope with their most important co-evolved threats.

Poster session B - GEN 2000

## Adaptation of plant pathogens to disease control on heterogeneous landscapes (52793)

**Alexey Mikaberidze.**

*ETH Zurich, Institute of Integrative Biology.*
Plant diseases often lead to severe crop losses in agriculture. Depending on the pathogen's dispersal range, disease control strategies should be coordinated over a scale of a single field, several adjacent fields or a regional spatial scale. We investigate population dynamics of host-pathogen interaction and pathogen adaptation to disease control using a spatially-structured population dynamical model coupled with a model describing pathogen adaptation. Favorable patterns of simultaneous application of fungicides and resistant host varieties to control major fungal diseases of wheat are explored over different spatial and temporal scales. An optimal disease control strategy will suppress the disease level in the short term and slow down or prevent pathogen adaptation in the long term.

Poster session B - GEN 2000

**Evidence for extrinsic postzygotic isolation between sympatric host races of leaf beetle Lochmaea capreae (52832)**

Shaghayegh Soudi, Klaus Reinhold, Leif Engqvist.

*Evolutionary Biology*, Bielefeld University, Germany; *Evolutionary Biology*, Bielefeld University, Germany; *Evolutionary Biology*, Bielefeld University, Germany.

Ecological speciation is a classic scenario for speciation in which reproductive isolation evolves between populations exploiting different habitats. We examined predictions of the ecological model regarding the fitness of hybrids between sympatric host races of leaf beetle Lochmaea capreae specialized on willow and birch host plants. The Survival of F1 hybrids, willow backcrosses and birch backcrosses, as well as both parent species, was evaluated on both parental host plants. The comparison of backcrosses survival on both host plants estimates an ecologically dependent component of their fitness while controlling for any intrinsic genetic incompatibilities that may exist between each race genomes. Our findings showed a striking pattern of ecological dependence: the switch in relative fitness of the backcrosses on the two parental host plants and the expected rank order of each cross type performance. These findings provide strong evidence that divergent natural selection has played some roles in the evolution of postzygotic isolation between the host races of L.capreae. Implications of these results provide a rare but strongly supported evidence of ecologically dependent postmating isolation during ecological speciation in nature.

Poster session B - GEN 2000

**Contrasting phylogeographic patterns of a phytophagous insect and its host plants (52884)**

Neus Marí-Mena, Carlos López-Vaamonde, **Horacio Naveira**, M. A. Auger-Rozenberg, Marta Vila.

Universidade da Coruña; INRA; Universidade da Coruña; INRA; Universidade da Coruña.
Gene pools become subdivided because of many different reasons, but it is generally quite
difficult to pinpoint the main factors contributing to that process. In each generation,
individual phenotypes are confronted with changing environments and their fitness is
assessed. If the bet to some variant proves correct, the prize can be a magnificent adaptive
radiation; if wrong, extinction is the maximum penalty, because some choices may become
irreversible. Systems formed by host plants and phytophagous insects are, a priori, very good
candidates for this kind of studies. In this communication we explore the phylogeographic
relationships between populations of the Spanish Moon moth Graellsia isabellae and those of
different Pinus spp. hosts. G. isabellae is a montane species whose larvae feed either on P.
sylvestris, P. nigra or P. halepensis, depending on the population. Attending to morphological
characteristics, the species is subdivided into five subspecies, associated to different mountain
systems. Our results indicate that the mitochondrial genomes of these subspecies are indeed
differentiated, that the time of coalescence of many of the identified mutations precedes the
LGM, and that none of the Pinus hosts offers a phylogeographic pattern completely
concordant with the relationships observed among them.

A parasite's dilemma: weediness-specialization conflict in Orobanche? (52894)

Salman Rahimi, Mohsen Beheshtian Mesgaran, Ali Ghanbari.

Ferdowsi University of Mashhad; The University of Melbourne.

Orobanche spp., (synonymous Phelipnahce) is the largest genus of obligate non-
photosynthetic holophrastic in Orobanchaceae family. Weediness is a human-mediated
character that co-evolved in some plants since human started cultivation of useful plants. In
Orobanche, weediness may come into conflict with parasite specialization that relays on
predictable resources such as association with perennial hosts in natural ecosystems.
Orobanche species differ in the host specificity and host range. Whereas a specific host is a
dimension of the n-dimensional hypervolume, host specificity and broad host ranges could be
considered as niche dynamics and extension in Orobanche. Most Orobanche species exhibit
high host specificity that is expected to lead to strong parasite specialization. Equilibrium
between these narrow host-range species and their hosts introduces a well-adapted
relationships on population level based on evolutionary adaptation. Broad host ranges and
physiological and ecological diversity of seed properties, e.g. dormancy, conditioning, great
longevity, very high seed output, are distinct characters to separate weedy from non-weedy
Orobanche. In anthropogenically disturbed habitats, Orobanche species occur in large
numbers on many annual hosts where they can be lethal to their hosts which implies a poorly-
adapted relationship. It is therefore hypothesized that the evolution of weediness in
Orobanche follows a trajectory that may contradict the parasite specialization.

Genetic basis of biogeographic variation in periodic timing of the parasitoid
Nasonia vitripennis (52901)
**Jelena Prodic**, Leo W. Beukeboom, Louis van de Zande.

*University of Groningen.*

Many organisms have evolved ways to timely anticipate periodic fluctuations in environmental conditions. Such time-keeping mechanisms detect and process biotic or abiotic external cues (such as photoperiod) and govern internal metabolic and physiological processes. One open question is to what extent the regulation of circadian timing is similar to that of seasonal timing. An example of seasonal timing is photoperiodic diapause induction. In Europe, the jewel wasp Nasonia vitripennis shows a geographicalcline in photoperiodic diapause induction which is correlated with genetic polymorphisms in the clock gene period. In order to determine the role of these polymorphisms, period alleles from field-derived lines of different latitudes were introgressed into a homogeneous laboratory line genetic background to investigate the effect on circadian activity and diapause induction. Subsequently, isofemale lines established from an intermediate latitude were tested for circannual periodicity in diapause induction. In addition, the dependence on temperature relative to photoperiod as cue for seasonal timing was compared between northern and southern lines. The results provide insight in the genetic regulation of an important life-history trait in response to different latitudinal conditions.

Poster session B - GEN 2000

**Host-parasite specificity in the Apis – Varroa complex in Asia (52926)**

**Paul Page**, Ninat Buawangpong, Zheguang Lin, Huoqing Zheng, Fu-Liang Hu, Panuwan Chantawannakul, Peter Neumann, Vincent Dietemann.

*Agroscope* – Swiss Bee Research Centre, Schwarzenburgstasse 161, Bern, Switzerland; Bee Protection Center, Department of Biology, Faculty of Science, University of Chiang Mai, Thailand; College of Animal Science, Zhejiang University, Hangzhou, People’s Republic of China; Institute of Bee Health, University of Bern, Bremgartenstrasse 109, Bern, Switzerland; Social Insect research Group, Dpt of Zoology and Entomology, University of Pretoria, South Africa.

Various haplotypes of ectoparasitic mites of the Varroa spp. naturally infest colonies of the Eastern honey bee Apis cerana and appear to be specific to their respective host populations. However, strong behavioral (reproductive) and genetic data are often lacking to ascertain the basis of this specificity. We investigated host specificity in the Apis-Varroa system at a higher resolution by cross-infesting, in vitro, mites from various lineages onto A. cerana populations at three locations in Thailand and one in China. We then genotyped mites that reproduced as well as those that did not, to confirm their haplotype. Host specificity was not exclusively explained by an absence of reproduction in putative new hosts. This approach allowed us to better define host specificity and will provide a solid basis to explain which traits, both in the genetically diverse parasite lineages and in the host species, are involved in or constrain novel host adaptation.
# Impacts of a hyperparasite on pathogen spread and virulence (52993)

Steven Parratt, Anna-Liisa Laine.

*University of Helsinki; University of Helsinki.*

The influence of intrinsic biotic and abiotic factors on the dynamics of infectious diseases is well studied. Yet the impact of a pathogen's own natural enemies, such as hyperparasites, on its spread and severity remains comparatively under-researched. Given the ubiquity of parasitism, and by extension hyperparasitism, we may be overlooking a key determinant of pathogen success or failure and thus coevolutionary dynamics. Previous studies have demonstrated that hyperparasites can reduce disease severity in infected host individuals, however the effect of hyperparasites on the population dynamics of pathogens remains enigmatic. Here, we combine laboratory experiments with field studies across a plant-pathogen metapopulation in order to demonstrate the impact of a mycoparasitic fungus (Ampelomyces sp) on key life-history traits of a powdery mildew (Podosphaera plantaginis). We hypothesized that the hyperparasite will curtail key fitness traits of the pathogen, potentially reducing disease severity at the population level and limiting its spread and persistence. Our results lend insight into the complexity of interactions between multiple species and raise further questions as to the evolutionary relationships within hierarchical chains of parasites.

# Phylodynamically estimated HIV diversification rates reveal prevention of HIV-1 by antiretroviral therapy (51816)

Jeffrey Joy, Richard Liang, Rosemary McCloskey, Thuy Nguyen, Chanson Brumme, Robert Hogg, Julio Montaner, P. Richard Harrigan, Art Poon.

*British Columbia Centre for Excellence in HIV/AIDS; Department of Medicine, UBC; Faculty of Health Sciences, Simon Fraser University.*

Treatment of HIV infection with antiretrovirals decreases transmission risk. Despite epidemiological evidence supporting ‘Treatment as Prevention’ quantifying this success remains a significant challenge. Phylogenetic analysis of viral sequence data yields crucial insights into epidemic processes, including transmission dynamics. We evaluated the impact of treatment on HIV transmission rates in the British Columbia (BC), Canada epidemic using phylodynamic methods. We recovered 27,296 anonymized HIV sequences from 7,747 HIV patients in BC annotated with: sample collection date, treatment status at collection, date of first antiretroviral treatment, and HIV risk factor. We inferred a distribution of phylogenetic trees under maximum likelihood. We calculated a lineage level phylogenetic branching rate for each HIV lineage in the trees, providing an approximate measure of transmission rates. Comparison of HIV branching rates between treatment-experienced and treatment-naive lineages across the BC epidemic as a whole, among risk factors, and among different drug classes revealed branching rates were significantly lower among treatment-experienced HIV
lineages relative to treatment-naive lineages (p<0.001), implying reduced rates of HIV transmission in the former and suggesting these results are not driven by penetrance of health care into particular risk groups or therapeutic regimens. Our results provide independent evidence that HIV treatment has limited onward transmission.

# Determining the heritability and molecular determinants of virulence in HIV in Europe using whole genome sequencing (51819)

**François Blanquart**, Chris Wymant, Marion Cornelissen, Luuk Gras, Astrid Gall, Paul Kellam, Christophe Fraser.

*Imperial College London; University of Amsterdam; HIV monitoring foundation; Sanger Institute.*

HIV is highly variable and subject to strong selection, and must therefore adapt rapidly to its host population. The set-point viral load (SPVL) in particular, a strong predictor of clinical outcomes, can be considered as a viral trait under selection. Understanding the evolutionary dynamics of SPVL requires knowledge of its heritability and genetic determinants. Current estimates of heritability vary widely (6% to 59%) and genetic determinants are largely unknown.

We use whole-genome HIV sequence from 802 patients of the UK and The Netherlands sampled between 1985 and 2014, coupled with SPVL and CD4 count for these patients, to investigate the genetic determinants of HIV virulence. Phylogenetics reveals a very good correlation between genetic distance to an outgroup and sampling date (R2=0.6) which allows a more precise dating of the origin of the HIV epidemic in Europe. A phylogenetic method estimates heritability of set-point viral load at a medium to high value with much narrower confidence intervals than previous estimates. Last, SPVL is higher when the patient is dually infected, and, intriguingly, also correlates with the nucleotidic composition of the sequence. A whole-genome association study (work in progress) will allow identification of SNPs associated with variation in SPVL.

# Phylogenetic reconstruction of viral quasispecies dynamics (51869)

**Veronika Boskova**, Tanja Stadler.

*Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland; SIB Swiss Institute of Bioinformatics, Basel, Switzerland.*

Especially in fast evolving and reproducing populations such as RNA viruses, the population of sequences present in one host at a time is often very rich but also very repetitive. Deep-sequencing approaches allow for quantification of sequences and their diversity.
The amount of sequences from such sequencing efforts represents a computational overload for current phylodynamic and phylogenetic model implementations in full Bayesian framework. Heuristic approaches aimed at reducing the computational burden apply the inference models only to the unique sequences, i.e. ignoring frequencies of the different sequences and instead assuming each one occurs only once, or to only a random subsample of the full dataset.

We set out to investigate these heuristics in terms of how much loss of information on dynamic properties of the process occurs. Based on the identified drawbacks of the heuristics, we propose a new tool for efficient reconstruction of viral epidemiological and evolutionary dynamics from full quasispecies datasets. The framework involves first reconstructing the haplotypes and their frequencies within the quasispecies from the raw reads. Phylogenetic analyses are then performed on the haplotype alignment and the frequency information. Use of such complete datasets should lead to a more complete picture of pathogen dynamics, insight into transmission bottlenecks, and in more reliable parameter estimation.

Poster session B - GEN 2000

# Phylodynamics on sexual contact networks (51894)

David Rasmussen, Tanja Stadler.

ETH Zurich.

We present a new modeling framework for understanding how sexual contact networks shape the phylogenic history of sexually transmitted pathogens like HIV. This framework is built upon a phylodynamic model that statistically describes how host network structure influences the shape of pathogen phylogenies by extending earlier coalescent models for infectious diseases to include local contact network structure. These phylodynamic models allow us to explore how network properties such as clustering, contact heterogeneity and assortative mixing shape tree structure. Moreover, this framework allows for network properties to be directly estimated from phylogenies using likelihood-based inference in a way that takes into account how network structure and epidemiological dynamics interact to shape a pathogen's phylogenetic history. We also demonstrate how these methods can be applied to real world HIV sequence data to test for differences in sexual contact structure among different human populations.

Poster session B - GEN 2000

# Metabarcoding bacterial and intestinal nematode communities in free-ranging rufous mouse lemurs (Microcebus rufus) (51895)

Tuomas Aivelo, Juha Laakkonen, Jukka Jernvall.

Institute of Biotechnology, University of Helsinki; Department of Biosciences, University of Helsinki; Department of Veterinary Biosciences, University of Helsinki.
There is strong interest in microbiome, but there is a lack of studies connecting intestinal
parasites and symbiotic bacteria. Nevertheless, we expect the species co-inhabiting intestine
to have interactions which shape their respective communities.

We mark-recaptured mouse lemurs for 3 years during the mating season in Ranomafana
National Park, Madagascar and tracked both microbiome and parasitic nematode community.
We were able to follow 21 individuals for multiple years.

We identified communities by metabarcoding approach: we used standard 16S gene approach to microbiome, while we developed a method to identify operational taxonomic units of nematodes from feces using 18S gene. We also collected data for other parasites, both intestinal eimeriids and helminths and ectoparasitic lice and ticks.

Within-individual parasite communities in mouse lemurs are shaped by facultative
hibernation as parasites seem to go extinct during hibernation and quickly (re)colonize
individuals after mouse lemurs' activity starts. While between-individuals community of the
parasites was stable over mating season, within-individual communities experienced drastic
turnover. In contrast, microbiome composition differed between individuals but microbiome
was stable throughout the sampling. There was no clear correlation between parasite
community and the bacterial composition. Nevertheless, the initial succession in microbiome
and parasite colonization after hibernation was very clear.

Poster session B - GEN 2000

Interacting species - interacting traits (52032)

Krzysztof Bartoszek.

*Department of Mathematics, Uppsala University.*

The need for multivariate methods is very well established in the phylogenetic comparative methods community. They are predominantly used to analyze co-functioning traits of the same species. However there is no methodological objection for using the same methods to analyze coevolution in a multiple species system e.g. host-pathogen, host-parasite. Apart from understanding how the species interact on the phenotype level such methods, like my mvSLOUCH R package, can aid in identifying the correct phylogeny from a set of competing trees (host species tree, virus tree, consensus tree ...) using trait measurements. I will discuss the mathematics behind modelling multiple traits evolving and speciating. I will then continue to show how one can use model selection of evolutionary models to find support for a species tree and illustrate it with a simple analysis of gene expression levels in different bacterial species.

Poster session B - GEN 2000

Killer bees or bee killers? the recent global spread of multi-host pollinator pathogens (52755)

Lena Wilfert.
University of Exeter.

Pollinating insects form communities that, in our temperate regions, are dominated by honeybees and bumblebees. Here, we show that viral pathogens, originally identified in the heavily studied honeybees, are generally multi-host pathogens that can freely circulate between species rather than being limited to honeybees. However, within these communities, some host species play a dominant role, which depends upon the insect community composition and the particular virus. Deformed Wing Virus is a formerly benign honeybee virus that has become a virulent emerging pollinator disease following the emergence of the varroa mite in European honeybees, which provide a novel horizontal transmission route. Using phylodynamic reconstruction, we show that this virus originated in East Asia but is now being propagated globally through European honeybee populations. This suggests that pathogens, and in particular RNA viruses, may be playing a role in the widespread declines of many pollinator species.

Poster session B - GEN 2000

# Ancestral polymorphism or recent gene flow? Insight from comparative genome scans in allopatry and sympatry (51863)

Mark Ravinet, Kohta Yoshida, Jun Kitano.

National Institute of Genetics.

How informative are genome scans for understanding speciation? Peaks and troughs of differentiation metrics have become a central focus in speciation studies yet relatively few attempts have been made to address the difficulties of interpreting these patterns. For example, does low divergence reflect gene flow or shared ancestral polymorphism? One way to deal with this is to investigate systems where it is possible to compare populations in sympatry and allopatry. If low divergence is due to shared ancestral polymorphism, we would expect no difference in differentiation between comparisons. We therefore focused on the recent speciation between two highly divergent three-spined stickleback species in the Japan Sea (Gasterosteus nipponicus) and the Pacific Ocean (Gasterosteus aculeatus). We constructed a large population genomic dataset of 280 individuals from sympatric and allopatric populations across the distributions of both species. Our spatially distributed sampling design allows us to identify introgression (lower differentiation in sympatry relative to allopatry) as well as candidate loci underlying reproductive isolation during divergence (divergence common to allopatry) and on secondary contact (divergence found only in sympatry). We suggest that careful consideration of study design can improve the interpretation of genome scan approaches.

Poster session B - GEN 2000

# Determining and managing adaptive potential in threatened populations – there is hope! (51928)
**Anna Santure**, Patricia Brekke, John Ewen.

*University of Auckland; Institute of Zoology, Zoological Society of London.*

For species of conservation concern, one of the most promising applications of genomics is to understand the genetic basis of adaptation in wild populations. For example, knowledge of genetic variants that increase or decrease fitness will be an important tool aiding decisions on which individuals should be translocated to found new populations, thus maximising evolutionary potential of the new population while reducing risk from deleterious variants. In this talk, I will give an overview of our work to date in developing a genomic toolkit to understand adaptive potential in the threatened New Zealand hihi (stitchbird; Notiomystis cincta). I will discuss more generally why I think there is hope for managing adaptive potential in threatened populations, with bottlenecks and inbreeding likely to have somewhat “simplified” the typically multi-genic architecture of quantitative trait variation. Borrowing from genomic prediction, I will argue that a thorough understanding of molecular mechanisms may not be necessary in order to accurately identify high value individuals for breeding programs and translocations, thus maximising the evolutionary potential of threatened species. However, as exemplified by excellent work from the Soay sheep group, gene mapping in pedigreed wild populations does offer exciting possibilities for understanding selection and evolution in the wild.

Poster session B - GEN 2000

# The never-ending effect of introgression on genome evolution in broadcast spawning marine species (52034)

**Christelle Fraïsse**, Khalid Belkhir, Camille Roux, Pierre-Alexandre Gagnaire, John J. Welch, Nicolas Bierne.

*ISEM; University of Cambridge; UNIL.*

Introgressive hybridization often leads to reticulated evolution in which diverging species remain connected by periodic gene-flow of different efficiency across the genome. Although widely accepted, its effect on patterns of divergence remains incompletely understood, mainly because of insufficient geographic and taxonomic sampling. Open questions are still numerous: How long can species boundaries remain permeable? Why are some genome regions more porous than others? How widespread are adaptive introgression, introgression swamping or local reshuffling of genetic barriers? We used reference genome assemblies to investigate introgression in two species complexes of broadcast spawning marine organisms: Mytilus mussels and Ciona sea squirts. Demographic inferences reveals that both species complexes are characterized by ongoing gene-flow despite strong molecular divergence (up to 0.15 in Ciona). Our analysis reveals wide variability in introgression rates along the genomes and across geographical samples. In sea squirts we uncovered hotspots of introgression due to adaptive introgression or genomic deserts of genetic incompatibilities. In mussels we observed a widespread contribution of differential introgression in generating geographic differentiation within species (up to half the intra-specific outliers). Reticulated evolution should be seriously considered when interpreting regions of outlying differentiation in
genome scans, especially when allelic divergence is old and taxonomic sampling has been
neglected.

Poster session B - GEN 2000

# Using population re-sequencing data to study patterns of genetic variation in butterflies. (52202)

Ramprasad Neethiraj, Emily Hornett, Jason Hill, Christopher Wheat.

*Stockholm University; Penn State University.*

Does recombination dynamics change across chromosomes? Does genetic variation vary across chromosomes? What is the relationship between recombination dynamics and genetic variation? Questions such as these fascinate our research community but are hard to answer in novel species in an economical and timely fashion without a high quality genome. Although advances in sequencing technologies make it possible to sequence whole genomes in days, effectively assembling and using such data is challenging. We have developed a method called MESPA (Mining Exons for Scaffolding Poor Assemblies) that takes as input a candidate protein gene set along with a low quality genome and returns high quality gene models. Using MESPA in combination with Pool-seq, I report on the patterns of genetic variation and recombination dynamics in a few species of butterflies without having had to invest time and money in a high-quality genome.

Poster session B - GEN 2000

# Genetic structure of populations with different B chromosome frequency assessed by two genome scan methods (52286)

Tanja Adnađević, Jelena Blagojević, Vladimir M. Jovanović, Ivana Budinski, Marija Rajičić, Mladen Vujošević.

*Institute for biological research "Siniša Stanković".*

B chromosomes present a diverse group of extra chromosomes heterogeneous in nature, behaviour, and evolutionary dynamics. B chromosomes in non-model organisms, such as yellow necked mouse, <i>Apodemus flavicollis</i>, has been in a focus of a long term research. In order to detect B chromosomes possible contribution to genetic structure of populations, we used samples from different habitat types, and with different frequency of animals with B chromosomes. Since whole genome coverage is required, genome scans employing neutral markers such as dominant amplified fragment length polymorphisms (AFLPs), and co-dominant microsatellites (SSRs) were performed. We obtained 471 AFLP markers and analyzed 8 microsatellite markers from 4 populations in Serbia. Consequently population and landscape genomic analysis was preformed. Characterization of the adaptive genetic variation in relation to environmental factors may contribute to the understanding of adaptive differentiation of populations to diverse habitats in species harboring extra
chromosomes. Limitations and advantages of used genome scan methods will be discussed in the light of B chromosome presence. This study will improve our knowledge of B chromosome maintenance and inheritance since 15% of all species posses them.

# Post-bottleneck genetics in wild populations: Do we see what we expect and do patterns differ from neutrality? (52424)

**Deborah Leigh**, Christine Grossen, Andreas Wagner, Lukas Keller.

IEU, University of Zurich ; Swiss Institute of Bioinformatics, Switzerland; The Santa Fe Institute, USA.

Bottlenecks, periods when a population is at a reduced size, are globally increasing in their frequency. Such declines can elevate extinction risk. Accordingly, an accurate understanding of their long-term consequences is required to optimize conservation management and mitigate the loss of biodiversity. Current understanding on the state of genetic variation and ongoing evolutionary processes after a bottleneck is predominantly from theory, laboratory experiments or neutral markers. In contrast, most bottlenecks occur in the wild. Wild populations are exposed to processes often naturally excluded from previous studies, such as variable environments and selection. These can affect the maintenance of variation and adaptive potential. Therefore, patterns in genetic diversity and evolutionary processes in the wild may deviate from expectations. Here we are examining genome wide SNP variation across several bottlenecked populations of Alpine ibex (Capra ibex). Through outlier scans and changes in allele frequencies across populations, we are investigating if marker patterns differ from neutral expectations and if recent selective events vary between populations. Ultimately, we aim to characterize genome wide variation and ongoing evolutionary processes across multiple wild bottlenecked populations.

# Estimating selection from clines across the genome (52441)

**Eniko Szep**, David Field, Nick Barton.

IST Austria.

In principle, narrow spatial gradients, or clines, indicate strong selection. However, with genome-wide data, it can be difficult to distinguish selected loci when they are embedded in a very large number of neutral loci. We simulate contact between distinct populations that meet in a one-dimensional habitat, following a linear genome that contains a few selected loci. We compare different methods for estimating cline widths and positions from marker frequencies, and show that the power to detect selected loci is limited by the time since contact and by the population density.
APPLICATION OF RESTRICTION-SITE ASSOCIATED DNA-
SEQUENCING FOR THE STUDY OF GENOMIC DIVERSITY AND
DIVERGENCE IN EASTERN BRAZILIAN MARMOSETS (52525)

Joanna Malukiewicz, Anne Stone.

Federal University of Viçosa; Arizona State University.

Here, we apply RADseq (restriction site associated DNA sequencing) in the characterization of intra- and interspecific genomic variation as well as divergence between two marmoset species, Callithrix jacchus and C. penicillata. These two species are the youngest members of the Callithrix genus, having diverged as sister species less than a million years ago. This study represents the first application of this technique to the Callithrix genus, and RADseq holds great potential to address several issues about the Callithrix phylogeny, identification of speciation genes, and hybridization. The main focus of this study is to establish the utility of RADseq in performing a Callithrix genomic scan, using 6 C. jacchus and 7 C. penicillata. The overall level of divergence between C. jacchus and C. penicillata was low at the variant sites recovered by RADseq STACKS analysis, but the former species showed less genetic variability than the latter. However, there are a number of genomic regions that showed high levels of statistically significant divergence, especially on chromosome 12, and these regions group into “islands” throughout the genome. The observed patterns of genomic variation and divergence will provide a foundation for future speciation and genomic studies within the Callithrix.

The remarkably limited explanatory power of molecular ecology (52646)

Patrick Meirmans.

University of Amsterdam.

We undoubtedly live in the era of genomics, with a continuous development of increasingly sophisticated molecular genetic tools. Together with those molecular tools, the statistical inferences used to analyse such data are getting increasingly refined. It has now become standard in analyses of population genetic data to estimate migration rates, barriers to gene flow, detect loci under selection, and associations between genetic and ecological variation. However, few users of these methods realise that their explanatory power is in fact highly limited and many of the methods are prone to biases and errors. Using results from my own research, I will explain several of these pitfalls and show when certain types of inferences can lead to erroneous results. I will then provide suggestions for the proper use of these analyses. Above all, I will warn against any overenthousiastic use of methods in cases for which they are not suited, which unfortunately includes the great majority of their applications.
# The blueprint of genomic architecture: does adaptation involve genetic trade-offs? (52777)

**Stuart Dennis**, Anamaria Štambuk, Dorotea Polović, Maja Šrut, Victor Soria-Carrasco, Zachariah Gompert, Vid Baković, Goran Klobučar, Patrik Nosil.

*The University of Sheffield; University of Zagreb; Utah State University.*

A central tenet of adaptive evolution is the differential fitness of genotypes in different environments. Theory suggests that these fitness differences may arise from genetic variability that is beneficial in some environments but deleterious in others, yet evidence to support this genetic trade-off is scarce. In this study we conducted a field transplant experiment and recorded differences in survival of 900 transplanted Mytilus galloprovincialis mussels in different environments. We use these survival data as a proxy for fitness in a genome-wide association scan with ~20,000 GBS variants. Our results show that fitness differs between environments and there is a genotypic signature involving around 60 genetic markers, but that these markers are different between environments. Our results challenge the hypothesis that adaptation involves genetic trade-offs. Implications of these data will be discussed.

# Analysing Evolve and Resequence Experiments (52789)

**Srdjan Sarikas**, Katarina Bodova, Nick Barton.

*IST Austria.*

Experimental studies of populations evolving in conditions with artificial selection (evolve and resequence experiments) are becoming more common due to more affordable sequencing technology. The candidates for selected loci are typically identified by strong increase in allele frequencies. However, determining a single locus as a selected one is virtually impossible since recombination does not break associations between loci on the typically short timescales of these experiments. Instead, selection acts on the whole blocks of linked loci from the original haplotypes, so it is the haplotype frequencies that carry the key information about the underlying evolutionary mechanisms, not the observed allele frequencies. We show how to reconstruct the haplotype frequencies from the pooled allele frequencies, how to bound the errors of the estimate, and how to optimally design the experiments.
# Genome-wide population differentiation and local adaptation in Atlantic cod
(52952)

**Michael Matschiner**, Bastiaan Star, Paul R. Berg, Ole K. Tørresen, Alexander J. Nederbragt, Olav S. Kjesbu, Nils Chr. Stenseth, Kjetill S. Jakobsen, Sissel Jentoft.

*Centre for Ecological and Evolutionary Synthesis, Department of Bioscience, University of Oslo, Oslo; Institute of Marine Research, Box 1870 Nordnes, N-5817 Bergen, Norway.*

Populations of Atlantic cod (Gadus morhua) are differentiated in a variety of phenotypic traits, including alternate life history strategy and migration behavior. In contrast to Norwegian local cod populations which reside near the coast all-year round, the North-East Arctic Cod is a highly migratory population, feeding most of the year in the open water of the Barents Sea, but spawning along the Norwegian coast, with the main spawning area at the Lofoten archipelago. Besides long-distance migration between the Barents Sea and the spawning area, the North-East Arctic Cod is further characterized by vertical migration and the use of deeper habitats, as well as the crossing of thermal fronts between warm Atlantic and cold Arctic waters. These differentiated populations of Atlantic cod could therefore represent an example of speciation in progress.

Here, we investigate genetic differentiation and patterns of selection between coastal cod and North-East Arctic Cod, using genome sequences of 48 individuals. We identify over 10 million single nucleotide polymorphisms (SNPs) and find strong support for genetic population separation between the two groups. We further characterize patterns of selection across the Atlantic cod genome and investigate the directionality of gene flow in different genomic regions.

Poster session B - GEN 2000

# Parental care buffers against inbreeding depression in burying beetles (51584)

**Natalie Pilakouta**, Seonaidh Jamieson, Jacob Moorad, Per Smiseth.

*University of Edinburgh.*

Inbreeding depression is a major evolutionary and ecological force that influences population dynamics and the evolution of mating systems. Inbreeding depression can be exacerbated by various environmental stresses, such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these stresses. We examined this potential role of parental care in a burying beetle with facultative care. We used a 2x2 factorial design with the following factors: (i) the presence or absence of the mother during larval development and (ii) inbred or outbred offspring. We hypothesized that maternal care would improve the performance of inbred offspring more than outbred offspring. Indeed, the mother's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the buffering effects of care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which
may favor inbreeding tolerance. These buffering effects could thus influence the evolution of mating systems and other inbreeding avoidance mechanisms.

Poster session B - GEN 2000

# Testing for Punctuated Evolution in New Zealand Marine Snails (Penion) (51588)

**Felix Vaux**, Simon F.K. Hills, James S. Crampton, Steve A. Trewick, Mary Morgan-Richards.

*Massey University; GNS Science; Victoria University of Wellington.*

Stasis and rates of evolution have been popular research topics since the beginning of evolutionary theory, but there have been few comprehensive, empirical investigations of the original (and controversial) predictions of 'punctuated equilibria.' We are testing these hypotheses using the supposed ideal dataset of Penion (Buccinidae, Neogastropoda).

The investigation integrates genomic and geometric morphometric analyses under a phylogenetic framework, and it combines living and fossil record data. The study genus exhibits significant extant diversity in New Zealand and Australia, and there is an exceptionally detailed fossil record extending to 27 Ma. Extant genetic lineages have fossil records reaching 5 Ma, this allows for changes in morphology to be directly linked to genetic variation, and for morphology-based taxonomic classification to be tested against population genetics. Individuals are large, morphologically complex, and developmental morphology is also preserved.

Preliminary mtDNA and rDNA phylogenetics indicates that Penion is paraphyletic with the geographically distant clade Kelletia, meaning that the possibility of allopatry and invasion (rather than geologically abrupt morphological change) is present in this supposedly ideal dataset. Based on current data however, the vast majority of extant lineages represent an Australasian-restricted monophyletic group. Ongoing analysis is testing the accuracy of morphology at predicting genetic lineages.

Poster session B - GEN 2000

# EVOLUTIONARY AND CONSERVATION GENETICS STUDIES IN Damithrax spinosissimus, the Caribbean king spider crab (51594)

**Julio Hurtado**, Nestor Campos, Edna Marquez.

*Universidad EAFIT, Medellín, Colombia - Universidad Nacional de Colombia Sede Medellín; CECIMAR, Universidad Nacional de Colombia Sede Caribe; Universidad Nacional de Colombia Sede Medellín.*
Damithrax spinosissimus is a large Majid crab distributed throughout the sub-tropical Atlantic Ocean in the United States of America, the Bahamas and the West Indies in the Caribbean Sea. There is a lack of information about evolution, conservation genetics and phylogeography aspects of this species. Oceanic and coastal islands from Caribbean Sea have differences in geological origins and environmental conditions and life history traits of D. spinosissimus populations (short larval period) could affect their distribution across Caribbean ecosystems. We present important information in evolutionary and conservation genetic aspects in D. spinosissimus by using molecular markers and ecological information. By using the 454 pyrosequencing approach, we assembled the nuclear and mitochondrial genomes and designed de novo primers for population genetics and phylogeography analysis in five Colombian populations of D. spinosissimus. We tested phylogenomic relationships of D. spinosissimus with other 43 crustacean species, and by using microsatellite and mitochondrial regions we found two management units (the first one an oceanic island, the second one four continental populations). This information may be important as a complementary study in molecular evolution of Malacostracan crustaceans, and for future studies in management strategies for marine protected areas and their conservation for food security in developing countries.

Poster session B - GEN 2000

**The evolutionary nature of high population density in insular lizards (51652)**

**Maria Novosolov, Gordon Roda, Anat Feldman, Amy Kadison, Roi Dor, Shai Meiri.**

*Tel Aviv University; US Geological Survey.*

Islands organisms usually have fewer predator and competitors species than mainland ones. This is thought to select for high population densities on islands. We hypothesize that insular lizards have denser populations than mainland species and that density is negatively correlated with competitor and predator richness. We collected population density data for 317 species – 94 small island species, 31 large-islands species, 32 mainland populations of species also found on islands and 160 from mainland ‘endemics’. We controlled for phylogenetic affinities, body mass and study area, which are strongly correlated with population density. Population density was the highest in small-island species and lowest in mainland ‘endemics’. Mainland populations of species also found on islands had higher population density than mainland ‘endemics’. Population density of insular species increases with decreasing lizard richness and NPP. Population density of mainland species increases in areas of low lizard species richness and predation risk. We hypothesize that the tendency to live in high population densities gives a ‘head start’ for species to successfully colonize islands. Interspecific competition has a strong affect in controlling population density thus species on lizard-poor islands can increase their population density even when NPP is low.

Poster session B - GEN 2000

**MOLECULAR SYSTEMATICS OF THE ASIAN SPECIES OF THE GENUS METAGONIMUS (51664)**
**Urusa Thaenkham**, Hideto Kino, Yukifumi Nawa, Tomáš Scholz, Jiraporn Ruangsittichai, Naowarat Saralamba.

*Department of Helminthology, Faculty of Tropical Medicine, Mahidol University;*
*Department of Infectious Diseases, Hamamatsu University School of Medicine, Hamamatsu,*
*Japan; Research Affairs Office, Faculty of Medicine, Khon Kaen University, Khon Kaen,*
*Thailand; Institute of Parasitology, Academy of Sciences of the Czech Republic. České*
*Budějovice, Czech Republ; Department of Medical Entomology, Faculty of Tropical*
*Medicine, Mahidol University, Thailand; Department of Molecular Tropical Medicine and*
*Genetics, Faculty of Tropical Medicine, Mahidol Univer.*

Metagonimus is genus of intestinal parasite in the family Heterphyidae. Metagonimus consists of seven nominal species in the oriental region and one in Europe. Among the oriental Metagonimus species, the relative sizes of oral and ventral suckers have been used as major morphological diagnostic characteristics, and these parasites have been divided into two groups. Group 1 consists of Metagonimus yokogawai, M. takahashii, and M. miyatai – their oral sucker is smaller than the ventral sucker. In contrast, species in Group 2 has an oral sucker larger than the ventral sucker, and consists of M. hakubaensis, M. katsuradai, and M. otsurui. In this study, these six oriental Metagonimus were collected from fish at different localities in Japan. Phylogenetic relationship was investigated by using three genetic markers, 28S rDNA, ITS 2 region, and cox1 gene. By molecular phylogeny, Metagonimus could also be divided into two clades. Four species were grouped together in clade I, except M. katsuradai, and M. otsurui which were in clade II. These two species were found to be very closely related genetically, and rather distantly related to M. hakubaensis, which is surprising considering their morphological similarities. It suggested that morphological characteristics alone are not enough for systemizing Metagonimus.

Poster session B - GEN 2000

**Male diapause exists in Drosophila montana; diapause affects CHC composition and mating behaviour in D. montana. (51735)**

**Outi Ala-Honkola**, Thomas Schmitt, Venera Tyukmaeva, Hannele Kauranen, Anneli Hoikkala.

*University of Jyväskylä; University of Würzburg; University of St Andrews.*

Environmental cues, mainly photoperiod and temperature, control reproductive diapause (arrest of oocyte development) in female insects. Diapause serves two adaptive functions: it improves survival during unfavourable seasons and/or restricts oviposition to the season favourable for the survival of eggs. Male diapause (defined as a reversible inability to inseminate receptive females) is much less studied than the female one, but if males maximise their chances to fertilize females while minimizing energy expenditure (sperm production is costly), we expect males to be in diapause at the same time as females are. We investigated whether male Drosophila montana are reproductively inactive when kept in conditions that induce diapause in females and we found that indeed, they are. We also found that males can recognise diapausing females as they do not court them. This is probably due to cuticular hydrocarbon (CHC) profile change in diapausing flies. Diapausing flies have more long-
chained hydrocarbons, which have been shown to increase desiccation tolerance in other Drosophila species, in their cuticula than non-diapausing flies. Males may use these as a cue to assess female reproductive state.

# Antibiotic restriction might facilitate the emergence of Multi-Drug Resistance (51776)

URI Obolski, Lilach Hadany.

*Tel Aviv University.*

High antibiotic resistance frequencies have become a major public health issue, and cause substantial limitations in treatment options for some bacterial infections. To diminish overall resistance, and especially the occurrence of bacteria that are resistant to all antibiotics, certain drugs are deliberately scarcely used - mainly when other options are exhausted.
We use a mathematical model to explore the efficiency of such antibiotic restrictions. The model is examined for two strategies of antibiotic prescription: cycling and mixing, in which the drugs are periodically switched, or randomly assigned, respectively. Data obtained from Rabin medical center, Israel, is used to estimate realistic antibiotic resistance frequencies in incoming patients.

We find that broad usage of the hitherto restricted drug can reduce the number of incorrectly treated patients, and reduce the spread of bacteria resistant to both common antibiotics. Such double resistant infections are often treated with the restricted drug, and therefore are prone to become resistant to all three antibiotics. Thus, counter intuitively, a broader usage of a formerly restricted drug can sometimes lead to a decrease in the emergence of bacteria resistant to all drugs. We recommend re-examining restriction of specific drugs, when multiple resistance to the relevant alternative drugs already exists.

# Evidence for the emergence of a lethal genetic disease in a wild bird population of conservation concern (51781)

Amanda Trask, Jane Reid, Stuart Piertney, Davy McCracken, Eric Bignal.

*University of Aberdeen; Scotland's Rural College; Scottish Chough Study Group.*

Populations of conservation concern are often small or inbred. Theory predicts that deleterious recessive mutations that are masked in outbred populations will be expressed, potentially leading to increased expression of genetic diseases. Few studies, however, have demonstrated the emergence of a deleterious recessive genetic disease in a wild population of conservation concern, meaning that the real world importance of such processes has been questioned. Red-billed choughs (Pyrrhocorax pyrrhocorax) have suffered an historic decline and currently number less than 60 breeding pairs in Scotland. This population has recently
been affected by a lethal disease characterized by blindness and associated brain abnormalities in nestlings. We used pedigree data to show that the pattern of occurrence of blindness within and among families matched that expected given Mendelian inheritance of a single-locus recessive mutation. Such analysis of observational pedigree data assumes an absence of extra-pair parentage, and indeed extra-pair parentage rates were estimated to be low (4.2-6.6% of offspring). A candidate gene approach, based on known genetic polymorphisms underlying the similar human condition ‘Peters’ anomaly’, did not detect polymorphisms associated with blindness in choughs. Nevertheless, we provide strong evidence of the emergence of a lethal recessive genetic disease in nature.

## Elephants born in the high stress season age faster (51803)

**Hannah Mumby**, Adam Hayward, Khyne U. Mar, Virpi Lummaa.

*University of Sheffield; University of Edinburgh.*

Senescent declines in reproduction and survival are found across the tree of life, however little is known of the factors individual variation in these rates, such as early developmental conditions. Only a few studies exist on the effects of early life environment on reproductive ageing and there are no studies beyond those of humans concerning very long-lived species. We use a large dataset (N=1078) of female working Asian elephants (Elephas maximus) from Myanmar to test these concepts. We analyse the effects of birth conditions, measured as concentration of stress hormones in reproductive-aged females, to categorise birth season into stressful vs. not-stressful periods. We show that the months in which adult females (potential mothers) have highest glucocorticoid concentrations and most intense workload are June to August; with a mean of 68.1ng/g feces compared to 45.6ng/g feces in the other months. Female elephants born in these months exhibit faster reproductive senescence in adulthood (interaction between age and birth season, X2(df=1)=6.07, P=0.014) and have lifetime reproductive success reduced by 15.9% in comparison to their counterparts born at other times of year. These findings have implications for our understanding of senescence theory and conservation strategies in endangered Asian elephants.

## Parallel divergence of landlocked freshwater gobies from an amphidromous ancestor in the Ryukyu Islands of Japan (51861)

**Yo Yamasaki**, Hirohiko Takeshima, Yuichi Kano, Mutsumi Nishida, Katsutoshi Watanabe.

*Kyoto University; Research Institute for Humanity and Nature; Kyushu University; University of the Ryukyus.*

The genus Rhinogobius is the largest group of freshwater gobies, consisting of ~85 species with several life-history types. Rhinogobius sp. YB is a landlocked form occurring in the
Ryukyu Islands of Japan, and previous studies suggested that its populations in respective islands or rivers originated by parallel divergence from the related amphidromous form (Rhinogobius brunneus). However, there have been no statistical comparisons between parallel and single origin hypotheses. To confirm the parallel landlocking patterns, we conducted genetic analysis using microsatellite markers. The genetic relationships among specimens supported polyphyletic patterns for landlocked populations, which seem to be derived from the amphidromous populations in the respective islands. Further, we performed statistical comparisons between alternative hypotheses on the origin of landlocked populations using the Approximate Bayesian Computation method. This analysis also supported the idea of independent origins of landlocked populations among islands. Moreover, the results suggested that the periods of their divergence differed among islands. Within islands, on the other hand, no positive support for the idea of independent origins of landlocked populations was obtained. The present study suggests that comparisons among landlocked populations in different islands will be useful to study the mechanisms and processes of parallel adaptation and speciation.

# Fine-scale genetic structure, distant matings and inbreeding depression in natural populations of Fucus vesiculosus (51868)

**Sara Teixeira**, Gareth Pearson, Rui Candeias Candeias, Céline Madeira Madeira, Myriam Valero, Ester Serrão.

CCMAR; CNRS, UPMC Sorbonne Université, PUCCh, UACH, UMI EBEA.

Restricted gene flow can lead to neighbouring individuals having higher genetic similarity among themselves than among distant ones. Here we studied small scale spatial genetic structure and mating patterns in the brown seaweed Fucus vesiculosus, a dioecious marine broadcast spawner. Given the mating system and life history traits of this species we expected to find spatial genetic structuring, and widespread heterozygote deficiency resulting from mating between neighbouring related individuals. F. vesiculosus occurs in habitats with contrasting exposures and patchiness, therefore we analysed 5 adult populations and recruits from 2 of these populations, in both natural open coast and estuarine ecosystems. Genetic diversity showed a North-South decreasing trend, while highly significant heterozygote deficits were found for most adult populations. The analysis of the recruits and their adult population seems to indicate the occurrence of inbreeding depression. The very fine spatial resolution of this study revealed a lack of spatial genetic structuring for three of the five populations studied, across different habitats. We propose three non-exclusive hypothesis for our findings:1) unrestricted gene flow 2) inbreeding depression eliminating most inbred individuals resulting from nearby related parents or 3) temporal Wahlund effects, through the genetic pool of a bank of microscopic forms.
# Quantifying clade-specific speciation and extinction rates from phylogenies (51906)

**Joelle Barido-Sottani.**

ETHZ.

With an increasing number of empirical phylogenies being available, it becomes possible to study the associated phylodynamics, i.e. the processes giving rise to the phylogeny, in great detail. Our work focuses on quantifying the speciation-extinction processes based on a phylogeny. In particular, we present a computational framework to identify clade-specific changes in speciation and extinction rates. We provide speciation and extinction rate estimates for each identified clade, and thus are able to quantify species-level selection patterns. Such analysis can produce useful hypotheses for downstream work on looking for the underlying reasons of rate changes.

We assess the reliability of our tool in a simulation study, and compare it to the existing BAMM (Bayesian Analysis of Macroevolutionary Mixtures) method, which uses a different conceptual setup to achieve the same goal of quantifying speciation and extinction rates. Finally we apply this tool, which will be available as an R package, to empirical phylogenies, demonstrating its performance on real data.

Poster session B - GEN 2000

# Strong genetic differentiation of the goby Rhinogobius duospilus in Hong Kong streams revealed by a multilocus approach (51948)

Tsz Huen Hu, I-Shiung Chan, Ka Hou Chu.

*The Chinese University of Hong Kong; National Taiwan Ocean University.*

Little is known about how regional landscape affects the genetic differentiation among fish populations on a small spatial scale. We report here the population genetics of Rhinogobius duospilus, an indigenous goby in Hong Kong (~1,104 km2). Analyses of mitochondrial genes (cyt b and CR) on >100 individuals from 25 localities recover four genetically distinct lineages with discrete geographical distribution. Two major, widely distributed lineages occur on the western and eastern sides of Hong Kong respectively, while two rare lineages are endemic to Lantau Island and Hong Kong Island respectively. Extensive genetic structuring is also observed within each lineage, even among streams of close proximity. The strong population structure is attributed to the local landscape such as mountain ranges and the poorly connected streams. On the contrary, analyses of nuclear markers (Rag 1 and RR-9) including microsatellites reveals a different population genetic pattern, with some alleles observed across mitochondrial lineages. The discrepancy between the two datasets may be due to factors such as incomplete lineage sorting of nuclear loci and strong genetic drift of mitochondrial genes. Our study suggests that the incorporation of information from analysis of nuclear markers is essential for reconstructing the evolutionary history of a species.
# On the importance of uncertainty quantification and modelling in regression covariates (51969)

Stefanie Muff, Lukas F. Keller.

*University of Zurich.*

Evolutionary Biology has become a very quantitative scientific field, and as such it relies heavily on the use of sound statistical methods. Regression models are probably the most popular tools to obtain inference from data. Important variables are, however, often difficult to measure and thus may contain considerable uncertainty or error. If such uncertainty is ignored, parameter estimates and confidence intervals of regression parameters often suffer from serious biases.

I will briefly discuss and illustrate the effects of measurement error in covariates when included in generalized linear (mixed) regression models. Two examples with inbreeding coefficients as covariates, where the latter were estimated from genetic data, will be presented.

The aim of my talk is to underline the importance of a careful quantification of uncertainties and measurement error in covariates or the outcomes of regression models. Given that the data collection process can be very time consuming and expensive, an extra effort in the analysis is often worth to obtain more precise answers to research questions.

# Understanding patterns of trait expression: trade-offs and correlations (51992)

Øistein Haugsten Holen, Thomas Owens Svennungsen.

CEES, University of Oslo.

The set of phenotypes an organism can develop is constrained. Traits that enhance fitness but are subject to a trade-off are usually predicted to correlate negatively. One well-known exception is when the units under study (e.g. individuals, populations) vary so much in state (e.g. resource level, condition) that the underlying trade-off is masked. We present a game-theoretical analysis of trait expression, using an organism with two defence traits as an example. Instead of a traditional two-way trade-off, we consider the more general case where one or both defence traits trade off with a third trait such as fecundity or growth. Both positive and negative correlations between the focal traits are found to be generic outcomes of the model, even in the absence of variation in state. A positive correlation can arise when variation in selection pressure causes variation in relative investment in the two focal traits versus the third trait across the units of study. The shape of the trade-off has a decisive influence on the outcome. We relate our findings to current empirical examples in the literature and discuss some of the pitfalls of using trait correlations as a shortcut for identifying trade-offs.
# Understanding the ecology and genetics of adaptive traits in Drosophila embryos (51993)

**Barbara Horvath**, Alex Kalinka.

*Institut für Populationsgenetik, Vetmeduni Vienna, Austria.*

Determining the genetic basis of fitness-related traits is crucial for understanding how populations adapt to their environments. By assaying phenotypes across different ecological settings, it is possible to uncover genetic variation responsible for adaptation in natural populations. Here we examined a fitness-related trait – the length of embryonic development – on the phenotypic level. By phenotyping 31 DGRP (Drosophila melanogaster Genetic reference Panel) strains, we uncovered genetic variation for the length of embryogenesis, measured as the median hatching time. We also characterized the egg-to-adult competitive fitness of these strains, both under low- and high larval densities, and found substantial Genotype x Environment interactions for fitness. By bringing together our phenotype data with information on previously measured phenotypes (zygotic genome activation, adult-to-adult competitive fitness) as well as genomic data, we have confirmed the ecological and evolutionary importance of the rate of embryonic development in D. melanogaster.

# Joint estimation of sibships and population parameters in the NGS era (52024)

**Thomas Ellis.**

IST Austria.

Pedigrees are powerful tools for investigating selection and mating patterns in wild populations. The power to infer pedigrees is improved by incorporation of information on phenotypes and sibships, but approaches which integrate both of these are currently lacking. Furthermore current software is not designed to deal with modern SNP data. I have been developing methods to jointly estimate pedigrees and evolutionary parameters which makes use of shared alleles among siblings, and which can deal with SNP data in minutes rather than months. I illustrate this with a half sibling arrays from open pollinated seed capsules from a snapdragon hybrid zone.525

# Molecular characterisation of MHC class II in the Australian invasive cane toad reveals multiple splice variants (52060)
**Mette Lillie**, Richard Shine, Katherine Belov.

*Faculty of Veterinary Science, University of Sydney; School of Biological Sciences, University of Sydney.*

The cane toad (Rhinella marina) has gained notoriety after its introduction and invasion across the Australian landscape, with significant impacts on the native Australian fauna. This invasion has shown rapid adaptation for dispersive traits, but at a cost to the immune system. To investigate their immunogenetics, we characterised the MHC class II in the Australian cane toad and found four class IIA and three class IIB loci. Very low allelic diversity was observed at all loci; the likely result of the complex history of introductions en route to Australia. We also observed two splice isoforms at two class IIA and two class IIB loci. One isoform seen at IIA and IIB loci involved the removal of the domain essential to peptide binding and presentation. The other isoform, observed at a class IIA locus is likely to be a soluble MHC product. This is the first observation of MHC class II splice variants in any anuran species, and similar splice variation has only been observed in caudate amphibians. These results suggest a significant role of MHC class II alternative splicing in the Australian cane toad, and may provide the first indication of it playing a wider functional role within Amphibia.

Poster session B - GEN 2000

A post-copulatory pre-zygotic barrier between collared and pied flycatchers (52083)

**Emily Cramer**, Murielle Ålund, S Eryn McFarlane, Arild Johnsen, Anna Qvarnström.

*University of Oslo Natural History Museum; Uppsala University.*

Post-copulatory, pre-zygotic (PCPZ) barriers are poorly studied in internally fertilizing vertebrates, but could play a major role in species that commonly copulate with heterospecifics. Pied (Ficedula hypoleuca) and collared (F. albicollis) flycatchers are closely-related species that occasionally form heterospecific breeding pairs, which is very costly due to the low reproductive success of hybrids. Extra-pair (EP) copulations with conspecifics, combined with PCPZ barriers, could mitigate the evolutionary cost of pairing with a heterospecific. We test one possible PCPZ barrier using an in vitro, blocked experimental design. Specifically, we examine the swimming speed of sperm from each species in fluid from the reproductive tract of females of each species. Pied flycatcher female fluid slowed down the swimming speed of collared flycatcher sperm, compared to all other female-male combinations. Females of both species have a higher proportion of EP offspring when socially paired to a heterospecific, but ecological factors make pied flycatcher females particularly likely to mal-adaptively pair with heterospecific males. The PCPZ barrier we document here may contribute to the heightened production of EP offspring by pied flycatcher females paired to heterospecifics, and it may be a substrate on which selection can act, strengthening the reproductive barrier between species.
# Population genomics on a non model fish species through Genotyping by Sequencing (52113)

Carlos Carreras, Enrique Macpherson, Marta Pascual.

Department of Genetics and IRBio, University of Barcelona, Av.Diagonal 643, E-08028 Barcelona, Spain; Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Car. Acc. Cala St. Francesc 14, Blanes 17300 Girona.

New genomic tools based on high-throughput sequencing enable the design and genotype of thousands of markers thus enhancing the power of classical population genetic analyses and bringing new research opportunities to date reserved to model species. However, their application to ecologically relevant species is not yet fully implemented due to the limitations of working without genome or transcriptome of reference. The East Atlantic peacock wrasse (Symphodus tinca) raises several ecological and biological relevant questions including the fine scale detection of oceanographic discontinuities, the assessment of adaptation under the scope of a global warming or the study of the effect of larval dispersion on population structuring. We used genotyping-by-sequencing (GBS) to develop a genome-wide panel of SNPs in 76 individuals from three populations under different environmental conditions in the Black and the Adriatic Seas. We obtained a set of 8,619 SNPs and genotypes suggested low inbreeding and similar variability across populations. We also found high levels of population differentiation, although inter-individual variation was higher than inter-population variation. Finally, the expected population structure was reconstructed and individuals were clearly grouped by populations. Thus, GBS is a very promising approach to develop markers for population genomics and adaptation studies in ecologically relevant species.

# MetaPIGA 4.0, maximum likelihood and Bayesian phylogenomics using Genetic-Algorithm and Monte-Carlo samplers (52128)

Djordje Grbic, Michel C. Milinkovitch.

LANE, Dept. of Genetics & Evolution, University of Geneva; SIB Swiss Institute of Bioinformatics, Switzerland; Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva.

The MetaPIGA phylogeny inference software has reached its fourth version with multiple new functionalities. First, the MetaPIGA user-friendly and intuitive graphical interface allows users to partition, visualise, and manipulate data as well as infer ancestral states based on Bayesian statistics. Note that command-line execution on local machines or remote clusters is also possible. Second, the user can choose to run analyses either on multicore CPUs or on GPU Nvidia graphics cards. The latter provides enough speedup for the use of codon models in practical computing time on single computer environments. Third, MetaPIGA 4.0 enables analyses of DNA, Protein, and codon data in the Bayesian and maximum likelihood frameworks with a palette of optimisation algorithms such as Hill climbing, Consensus
Pruning, and MC3.

Access of multiple algorithms in a single software allowed us to estimate their relative computing efficiencies and accuracies through comparisons of final tree likelihood, posterior probabilities, and execution time. Finally, we propose a modification of the Consensus Pruning algorithm that transforms it into a Markov Chain Monte Carlo sampler.

Poster session B - GEN 2000

# Disentangling the complex evolutionary history of the Western Palearctic blue tits (Cyanistes spp.) – phylogenomic analyses suggest radiation by multiple colonisation events and subsequent isolation (52189)

**Martin Stervander**, Juan Carlos Illera, Laura Kvist, Pedro Barbosa, Naomi P. Keehnen, Peter Pruisscher, Staffan Bensch, Bengt Hansson.

*Molecular Ecology and Evolution Lab, Dept of Biology, Lund University, Lund, Sweden; Research Unit of Biodiversity (UO-CSIC-PA), Oviedo University, Campus of Mieres, Asturias, Spain; Department of Biology, University of Oulu, Oulu, Finland; Present affiliation: Population genetics, Dept of Zoology, Stockholm University, Stockholm, Sweden.*

Isolated islands and their often unique biota play key roles for understanding the importance of drift, genetic variation, and adaptation in the process of population differentiation and speciation. One island system that has inspired and intrigued evolutionary biologists is the blue tit complex (Cyanistes spp.) in Europe and Africa, in particular the complex evolutionary history of the multiple genetically distinct taxa of the Canary Islands. We combined Sanger sequencing at a population level (20 loci; 12,500 nucleotides) and next generation sequencing of single population representatives (>3,200,000 nucleotides), analysed in coalescence and phylogenetic frameworks. We found that (i) Afrocanarian blue tits are monophyletic and represent four major clades; (ii) the blue tit complex has a continental origin, and that the Canary Islands were colonised three times; (iii) all island populations have low genetic variation, indicating low long-term effective population sizes; (iv) populations on La Palma and in Libya represent relicts of an ancestral North African population; and (v) the Canary Islands, contrary to recent suggestions, hold sink populations, which have not served as source for back colonisation to Africa. Our study demonstrates the importance of complete taxon sampling and an extensive multi-marker study design to obtain robust phylogeographical inferences.

Poster session B - GEN 2000

# Phylogeny and biogeography of Primula sect. Armerina in the Qinghai-Tibetan Plateau (52234)

**Guangpeng Ren**, Elena Conti, Jianquan Liu, Nicolas Salamin.

DEE; Institute for Systematic Botany, University of Zurich; Lanzhou University; DEE.
Understanding what shapes geographical and ecological distribution of biodiversity is one of the most challenging questions in evolutionary biology and ecology. This is particularly true for the regions that have experienced rapid habitat changes and harbor high species diversity. In this context, we firstly examined the diversification history of Primula section Armerina on species level based on five chloroplast DNA fragments and one nuclear gene. Our dating analysis based on chloroplast dataset suggested that this section began to diverge from its relatives around 3.55 million years ago, which largely coincided with the last major uplift of the Qinghai-Tibetan Plateau (QTP). Incongruences between the chloroplast and nuclear trees are mostly present among closely related species, which might be accounted for hybridization and/or introgression. Biogeographical analysis supports the origin of the section in the Himalayas Mountains and the dispersal from Himalayas to Northeast QTP, West QTP and Hengduan Mountains. Secondly, three very interesting species, P. fasciculata, P. tibetica and P. nutans, are chosen as our study materials to further investigate their phylogeography and population genomics using double digest RAD sequencing on population level. The data is collecting, and some of the results will be present in this poster.

# Quantifying Nature's appearance: combining high-resolution, coloured 3D reconstruction and mathematical tools to analyse skin patterns in Pantherophis guttatus (52279)

António F. Martins, Michel C. Milinkovitch.

*Laboratory of Artificial & Natural Evolution, Dept. of Genetics & Evolution, University of Geneva; SIB Swiss Institute of Bioinformatics, Switzerland.*

An expanding number of studies investigate the biophysical mechanisms generating intra- and inter-specific complexity and diversity of morphological traits. However, classification of morphologic characters is often limited to qualitative descriptions or simple quantitative analysis. To address this issue, we have combined state-of-the-art robotics, high-resolution digital cameras and image-based 3D reconstruction algorithms to build a scanning system capturing geometry and colour texture details down to 20 microns. This system is (i) greatly flexible, allowing a scanning range that extends from above the meter to sub-millimeter details; (ii) highly repeatable, making it suitable for a systematic approach; (iii) fast, with scanning times below 5 minutes, a critical feature when animals under anaesthesia are used. These fully-coloured 3D virtual mesh models are accurate representations of the real animal and its external morphological traits. This allows for the systematic and rigorous quantification of features such as colour variations and gradients, repetitive patterns, shapes, areas, or correlation among specific traits. Moreover, they can be used to perform numerical simulations of biophysical processes on realistic geometries. By using the colour patterns of corn snakes (Pantherophis guttatus) as an example, we argue that this approach has practical importance for innovative biophysical analyses of phenotypes in 3D.
**Endogenous control of sexual size dimorphism: Gonadal androgens have neither direct nor indirect effect on male growth in a gecko (52326)**

**Lukas Kubicka**, Zuzana Starostova, Lukas Kratochvil.

*Charles University in Prague, Faculty of Science, Department of Ecology; Charles University in Prague, Faculty of Science, Department of Zoology.*

Changes in the effect of gonadal androgens (GA) on male growth are considered to be the proximate mechanism of evolutionary shifts in sexual size dimorphism (SSD) in reptiles. Positive effect of GA on male growth was found in male-larger species of squamates, while negative in female-larger species. Nevertheless, previously we documented that in geckos, GA do not affect male growth under constant thermal conditions. This discrepancy could be attributed to effect of GA on thermoregulation and selection of body temperature, which might affect metabolic rate, general activity and hence indirectly growth. We tested this possibility by monitoring growth of control and castrated males in the male-larger gecko Paroedura picta kept in the thermal gradient. We did not find any differences between treatment groups in growth rate and final body size. Castration affects neither oxygen consumption nor foraging activity of experimental geckos. In conclusion, GA seems to have neither direct nor indirect effect on the ontogeny of SSD in geckos and the evolutionary changes in SSD in this group cannot be connected to evolutionary changes in GA metabolism.

Poster session B - GEN 2000

**Genetic relatedness does not predict the queen's successor in the primitively eusocial wasp, Ropalidia marginata (52335)**

**Saikat Chakraborty**, Thresiamma Varghese, Shantanu Shukla, Javaregowda Nagaraju, K P Arunkumar, Raghavendra Gadagkar.

*Centre for Ecological Sciences, Indian Institute of Science; Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500001; Deceased.*

Ropalidia marginata is a tropical paper wasp in which queens and workers are morphologically indistinguishable. Colonies consist of a single docile queen and up to 100 functionally sterile workers. Once the queen is dead or experimentally removed, one of the workers increases her aggression and eventually becomes the next queen. The chance of a worker succeeding the queen has been shown to be uncorrelated with her body size, dominance rank, ovarian or mating status, but imperfectly correlated with her age. Here we investigate whether genetic relatedness predicts the queen's successors. We first estimated pair-wise genetic relatedness using polymorphic microsatellite markers. Next, we constructed models based on successors i) being most closely related to the queen, ii) being most closely related to the immediate predecessor queen, iii) having the highest relatedness to the majority of the workers and iv) having the highest average relatedness to all the workers. We predicted up to five successors based on each of these models after performing experiments to determine up to five successors in experimental colonies. The predictions of none of the models matched the experimental results. Thus genetic relatedness does not predict the queen's successors in this species.
# Phylogenetic (in)stability of G and B matrices in Acridid grasshoppers (52336)

Anasuya Chakrabarty, Holger Schielzeth.

Bielefeld University.

Adaptive evolution is influenced by the fitness landscape and by the amount of heritable variation. But traits do not occur in isolation, since they are often genetically correlated due to pleiotropy or linkage disequilibrium. This causes non-independent inheritance of trait variation and influences the response to selection. The additive genetic variance-covariance matrix G efficiently summarizes the underlying genetic architecture and dependencies among traits. The size and structure of G can act as a constraint to adaptive evolution if the leading eigenvector of G (gmax) is not aligned with the selection vector. We estimate and compare the additive genetic covariance structure of five morphological and five song traits in three Acridid grasshopper species in order to assess the degree of phylogenetic stability of the G matrix. G matrices might diverge by genetic drift or by selection. Knowledge about the phylogenetic relationships among the three species allows us to ask if closely related species are more similar in the G matrices and if species divergence is biased towards gmax. Furthermore, we explore the structure of the matrix B, a submatrix of G that summarized cross-sex genetic covariances. This sheds light on sex-specific genetic variation and the evolution of sexual dimorphism in grasshoppers.

# Fishery-induced selection: what can be learned from introduced salmonids in Sierra Nevada Lakes? (52337)

Sébastien Nusslé, Stephanie Carlson.

University of California Berkeley.

Size-selective fishing is expected to trigger evolutionary responses. However, the potential for fishery-induced selection to significantly modify population characteristics is controversial and not yet well understood. In this study, we analyzed data from over 30 populations of brook trout and rainbow trout that were completely removed from lakes in California's Sierra Nevada during the course of a habitat restoration program. We estimated fishery selection on body length in replicate populations, and related the strength of fishery selection to population- and habitat-specific characteristics. Even though "non-selective fishing gear" was used in removal efforts, we found that fishing was more likely to remove larger individuals. Due to this size selectivity, we observed a dramatic decline in the mean and variability of fish length within a few months across populations. The magnitude of this decrease can be linked to population-specific parameters, such as initial size distribution and local environmental factors (e.g. lake size, elevation). Our study demonstrates that size-selective fishing not only
affects population structure by removing the largest individuals, but also that the environment
can mediate the impact of fishing.

Poster session B - GEN 2000

Experimental reduction of penis length reduces male reproductive success in a bug (52444)

Liam Dougherty, David Shuker.

University of St Andrews.

Animal genitalia are some of the most elaborate and fastest evolving traits we know of. It is now clear in many species that genital morphology in both males and females has been shaped by sexual selection. However, it has historically been difficult to confirm correlations between morphology and fitness, as genital traits are complex and manipulation tends to impair function significantly. The seed bug Lygaeus simulans has a long, coiled intromittent organ (or processus) that is threaded into the female spermathecal duct during mating. The processus is a hollow, sclerotized tube, and thus can be shortened easily by cutting. We confirm that there is significant selection acting on male processus length in L. simulans by experimental shortening of the processus prior to mating, and show that males with shortened processi have significantly reduced reproductive success. Importantly though, the sperm transfer function of the processus is not impaired by the manipulation itself. Such manipulation of a genital trait directly involved in sperm transfer has been reported only once before in the literature to our knowledge. We thus present rare, direct experimental evidence that an internal genital trait functions to increase reproductive success.

Poster session B - GEN 2000

Phylogenetic origins of the avian MHC Class IIB (52445)

Julien Goebel, Reto Burri, Marta Burri-Promerová, Luca Fumagalli.

Department of Ecology and Evolution, Laboratory for Conservation Biology, Lausanne
University; Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala
University ; Department of Medical Biochemistry and Microbiology, Biomedical Centre,
Uppsala University.

Gene duplication is thought to be one of the primary sources of adaptive evolution. The major histocompatibility complex (MHC) multigene family is a well-known example of an important ecological novelty coming from duplication events. It encodes genes involved in the vertebrates' adaptive immune response and stands for the most polymorphic genetic system known to date in vertebrates. Its frequent gene duplications and losses result in a marked variation in gene number and genomic organization between vertebrates. Mammalian MHC Class II β chain (MHCIIIB) paralogs evolve independently and their duplication history can be traced back over tens of millions of years. Recent studies on birds report also strong
evidence for the persistence of two ancient MHCIIB lineages (DAB1 & DAB2) over at least
100 million years, unequally distributed between bird species. We isolated and recovered
MHCIIB genes from species all over the avian phylogeny. We figured out mechanisms that
broke the duplication signal by reconstructing avian MHCIIB recombination and selection
histories, and assessing its concerted evolution pattern. Thus, we could identify gene regions
that reflect the history of the duplication. We reconstructed the phylogenetic history of avian
MHCIIB and provided an accurate estimate for the origin of the two ancestral lineages.

Poster session B - GEN 2000

Role of gamete and propagule dispersal in shaping the genetic distribution of sessile organisms (52489)

Valeria Montano, Samuel Neuenschwander, Jerome Goudet.

University of Lausanne; University of Lausanne; University of Lausanne.

Dispersal employs different strategies in sessile and motile organisms. Among terrestrial
plants, complex dispersal behaviours, involving multiple traits (dispersal syndrome) and
interaction with vector species, are well known in relation to seed dispersal. During the life
cycle of sessile organisms, dispersal may also happen at a previous stage, i.e. during gametic
production. These two dispersal stages (gamete and propagule) contribute differently to the
spatial and temporal distribution of genetic variation. In fact, a new genetic variant introduced
into a population may be carried in higher number of copies by n propagules than by n
gametes. Moreover, the two processes are likely to drive temporal fluctuations in the
distribution of genetic variation. Here, we perform a simulation study of the differential role
of gametic and propagule dispersal in shaping allele distribution, using a simple model of
sessile organism facing two dispersal stages.

Poster session B - GEN 2000

Individual experience affects how zebra finch males attend to physical
properties of nest materials (52508)

Alexis J. Breen, **Eira Ihalainen**, Eric Bowman, Susan D. Healy.

University of St Andrews.

Nest building is almost ubiquitous among bird taxa but the nest produced is immensely
varied. Within a single species the materials used to construct the nest can also vary
enormously, but we currently know very little of how birds 'know' what kind of a nest to
build. For a century, nest building has been assumed to be 'instinctive' but recent evidence
shows construction behaviour to be experience-dependent. We tested whether birds choose
structurally suitable building materials based on their own experience with those materials or
whether they have rules for selecting what to build with. In a laboratory experiment, we first
tested male zebra finches' (Taeniopygia guttata) initial preference for four types of material
that differed in length and/or rigidity (the male selects and deposits the material at the nest site). The males then built using one of these materials, after which their preference was tested for the second time. The changes in the males' preferences suggest that their choices depend on their building experience in a way that indicates they attend to physical properties of nest materials in a hierarchical fashion.

# Does phenotypic integration constrain morphological diversification? A phylogenetic comparative study (52524)

Masahito Tsuboi, Niclas Kolm.

Uppsala University, Evolutionary Biology Centre, Department of Ecology and Genetics/Animal Ecology; Stockholm University, Department of Zoology/Ethology.

Organisms need their parts to be integrated to function as a coherent whole, while a degree of modularity between functionally independent subunits is a ubiquitous feature of organismal design. Though theory predicts that the degree of phenotypic integration and modularity can influence the direction and the rate of evolutionary processes (the phenotypic integration hypothesis), empirical evidence is still scarce. Here, we investigated the key theoretical prediction that phenotypic integration constrains morphological diversification using craniofacial morphology of Lake Tanganyika cichlids, a well-known model system of morphological adaptation. We first employed geometric morphometrics to quantify the degree of phenotypic integration and modularity within cichlids' craniofacial system. Then, by explicitly taking phylogeny into consideration, we investigated the rate of morphological diversification in relation to the level of phenotypic integration. Specifically, we focus on four functionally significant traits in the cichlids' cranium; oral jaw morphology, brain size, eye size, and cheek muscle size. The result will be interpreted and discussed in light of the phenotypic integration hypothesis.

# POPULATION STRUCTURE OF THE COCONUT CRAB BIRGUS LATRO (DECAPODA: ANOMURA: COENOBITIDAE) FROM CHRISTMAS ISLAND IN THE INDIAN OCEAN (52533)

Christiana Anagnostou, Christoph D. Schubart.

Department of Evolutionary Ecology and Genetics, Zoological Institute; Biologie I, Institut für Zoologie, Universität Regensburg, D-93040 Regensburg, Germany.

There is increasing evidence for a lower degree of population connectivity and a higher degree of self-recruitment in marine species with planktonic larvae than expected under a passive dispersal model, giving rise to population sub-structuring. We assessed the genetic and biometric population structure of a terrestrial anomuran crab species with marine
planktonic larvae, the coconut crab Birgus latro on Christmas Island (Indian Ocean) using seven polymorphic microsatellite markers and morphometry. Adult individuals were sampled at five different locations (≈ subpopulations), with 20 individuals per location. A number of biometric measurements were taken as well as haemolymph and tissue samples for DNA extraction and subsequent microsatellite analysis. Results of genetic structuring analyses do not suggest an obvious population subdivision: Global and pairwise FST values were low; Bayesian methods and a principal component analysis did not reveal any population sub-structuring. The results of a population assignment test using estimated allele frequencies were ambiguous depending on the statistical method (17% versus 90% of individuals assigned to the subpopulation where they had been sampled), probably due to the low sample size. Regarding the biometric measurements, significant differences among some of the subpopulations could be detected. In conclusion, B. latro may so far be considered as a single management unit on Christmas Island.

Poster session B - GEN 2000

# The role of kinesin in the regulation of a quantitative colour trait (52570)

**Jesper Fogelholm.**

*IFM Biology.*

The genetic regulation of coat colour is one of the most studied gene systems to date, with ~150 genes known to be involved. Currently, however, all have Mendelian, rather than quantitative, effects. Using QTL mapping in two intercross chicken populations we identify a 2Mb region associated with the intensity of red colouration. This region contained a selective sweep (fixed in domestic birds), with five genes in close proximity. Expression of Kinesin-like-protein7 was found to strongly correlate with intensity of red colouration in feathers from juvenile Red Junglefowl x White Leghorn backcross individuals, as well as from separate adult RJF x WL intercross individuals. Microarray analysis of all genes in the QTL interval using multiple intercross individuals revealed KIF7 to be the sole candidate correlating with feather coloration. To the best of our knowledge this is the first time that a gene regulating a quantitative colour trait has been identified. Strikingly a kinesin has been shown to be involved in red colouration in butterflies from the Heliconius family. If this is the same mechanism at work, it suggests that this is functionally conserved, with 550 m.y.o to the last common ancestor, the Urbilaterian.

Poster session B - GEN 2000

# Explaining the variation in gestation length and weaning age across mammals (52596)

**Renske Gudde, Andrew Meade, Jeffrey Joy, Chris Venditti.**

*University of Reading; University of British Columbia.*
Mammalian length of gestation and weaning period differ remarkably. Furthermore, it has recently been suggested that these traits are coupled; when gestation length increases, lactation time decreases and vice versa. We studied the variation in gestation length and weaning age for 491 species of four mammalian orders, artiodactyls, carnivores, primates and rodents, and within these orders on the family level. By calculating the rate of evolution of these traits, we are able to explain when and how this variation has evolved, what other life history traits affected gestation length and weaning age and if they are indeed coupled traits. We found that the rates of gestation length and weaning age are affected by different life history traits and vary highly among orders (and families within orders). For example, in artiodactyls gestation length depends on the age of sexual maturity, the rate of gestation length is affected by litter size and neonatal body mass, weaning age is determined by litter size and maximum longevity and the rate of weaning age evolution by diet. Finally, the rates of evolution suggest that gestation length and weaning age are coupled in primates, but not in the other orders.

# Colonization pathways, genetic diversity and inbreeding depression in non-native lizards (52602)

Sozos Michaelides, Geoffrey While, Tobias Uller.

University of Oxford ; University of Tasmania; Lund University.

Studying biological invasions may further our understanding of how ecological and evolutionary processes shape patterns of diversity within species and communities. The ability of non-native species to persist and adapt to new environments is expected to rely on their genetic diversity. To understand what shapes their genetic structure we need to have a detailed knowledge of their colonization history. In this study, we used Bayesian clustering, approximate Bayesian computation methods and network analyses to reconstruct the origin and colonization pathways of 23 populations of the wall lizard Podarcis muralis in England. We then inferred how genetic diversity is affected by the origin(s) and admixture of distinct genotypic lineages. Our analyses show that established populations in southern England originate from at least nine separate sources from native populations in France and Italy. Genetic diversity was significantly lower in the non-native populations but mixed-origin populations had higher genetic diversity than single origin populations. The loss of genetic diversity was accompanied by increased hatching failure in non-native populations. This study thus demonstrates the importance of understanding colonization history for understanding the persistence and adaptation of non-native species.

# Relation between sex specific hormones (testosterone, progesterone) and sex specific traits in the Barn owl (Tyto alba) (52625)

Paul Béziers, Alexandre Roulin, Wolfgang Goymann.
Natural selection exerted on a given trait shared by both sexes can act differently in males and females. Given that sexual dimorphic traits are commonly under control of sexual hormones, it is likely that sexual selection acting on sexually antagonistic traits indirectly acts on sexual hormones or, alternatively, that sex hormones are directly responsible for sexual conflicts. We examined whether blood-circulating levels of testosterone and progesterone in barn owl nestlings (Tyto alba) were sex specifically related to melanin-based traits. Colour traits that are known to be under antagonistic sexual selection in this species. This study shows that nestlings displaying female specific traits, so large eumelanic spots and dark pheomelanic traits, had higher levels of progesterone than nestlings displaying male specific traits. And inversely, nestlings sired by males with male specific traits, so small eumelanic black spots, had higher levels of testosterone than nestling displaying female specific traits. Our results suggest that plumage traits in barn owls seems to signal the levels of sex hormones and thereby support the association found between melanin-based traits and sex-specific behavior in barn owls. These results also support the idea that sexual antagonistic selection observed in coloration may also exist for sex hormones

# No evidence for reproduction-lifespan tradeoffs in females of a Drosophila long-lived insulin-signaling mutant, under varying exposure to males (52684)

Irem Sepil, Pau Carazo, Stuart Wigby.

Across a broad range of taxa, similar factors mediate female lifespan: mating, reproduction and high levels of insulin-signaling all tend to reduce longevity. Although lifespan extension in insulin signaling mutants are often accompanied by reduced fecundity, exceptions to this pattern have been reported. This conflicts with life-history theory, which predicts an obligate trade-off between reproduction and lifespan. However, studies of long-lived mutants tend to be conducted under specific mating conditions, and often fail to consider other factors such as egg-adult viability, which may mask potentially important fitness effects. We varied the exposure to males of robustly long-lived Drosophila melanogaster females, in which key insulin producing cells are ablated. Ablated females always lived longer, had decreased fecundity but higher egg-adult viability than controls. However ablated females that received intermediate levels of exposure to males showed the highest increase in lifespan and no overall decrease in reproductive success. Lifespan extension under continuous exposure to males was likely mediated by reduced mating rates of the ablated females. Our results conflict with life-history theory, and instead suggest that optimal exposure to males and reduced insulin signaling result in maximal lifespan and reproduction for females.
Evolution of multiple trade-offs in a predator-prey system (52685)

Noemi Woltermann, Lutz Becks.

*Community Dynamics Group, Dept. Evolutionary Ecology, Max Planck Institute for*
*Evolutionary Biology,.*

Trade-offs are often perceived as a gain in one trait combined with a loss in another and are
often used to explain the maintenance of intra- and interspecific variation. They are however
typically viewed to occur between two different traits and little is known about the evolution
of trade-offs between a higher numbers of traits. Here we present results from a study where
we followed the evolution of traits in the green-algae Chlamydomonas reinhardtii when
evolving with and without predation by a rotifer (Brachionus calyciflorus). After 6 months,
we isolated several clones from each evolving population and measured algal growth rates
and palatability, survival of the predator when feeding on the evolved clones, as well as
diversification (morphology) and colony formation of the isolates. We found lower growth
rates, more colony forming genotypes, and lower rotifer survival rates for the isolates from
the predation treatment. We found however no difference in diversification between
treatments. Testing for multidimensional trade-offs, we found that different strategies
evolved. Overall we show that (I) trade-offs evolve repeatedly but different with and without
predation, (II) the evolution of traits depends on the genetic background of the ancestor and
(III) colony formation evolves as defense against predation.

Poster session B - GEN 2000

Hybridization capture using RAD-seq probes: a novel technique improving
data quality and among-sample overlap (52689)

**Camille Pitteloud**, Tomasz Suchan, Anna Kostikova, Nadezhda S. Gerasimova, Nadir Alvarez.

University of Lausanne; InsideDNA Ltd., United Kingdom; School of Biology, Lomonosov Moscow State University.

Development of next-generation sequencing brought new dynamics into evolutionary biology, allowing a dramatic increase in the representation of loci and specimens in population genomics studies. The most frequently used technique to reduce genome complexity in a reproductible manner is restriction-associated-DNA sequencing (RAD-seq). However, restriction site heterogeneity in RAD-seq can cause imbalanced loci representation and complicate data processing. In addition several sources of noise identified in RAD-seq can make data analysis more difficult. Here we describe a novel method, which improves among-sample locus overlap and strongly reduces stochastic variations in sequences outputs. The technique relies on the capture of shotgun Illumina librairies by molecular biotin-labelled probes that anneal to streptravidin beads. While probes generation can be PCR-based, using baits made of RAD-seq libraries allows whole genome scanning and avoids biases encountered in standard procedures. The method also applies well to historical DNA, characterized by high contaminant load that can thus be filtered prior to sequencing. The
approach described here offers extensive flexibility of applications and substantially improves
RAD-seq potential in producing high-quality data.

Poster session B - GEN 2000

Tracing the invasion history of Europe's worst slug pest (52736)

Miriam A. Zemanova, Eva Knop, Gerald Heckel.

Institute of Ecology and Evolution, University of Bern, Switzerland; Swiss Institute of Bioinformatics, Lausanne, Switzerland.

Invasive species are one of the major threats to global biodiversity. The slug Arion vulgaris (syn. lusitanicus) is considered one of the hundred most invasive species in many European countries and a major agricultural pest but its origin and routes of expansion are contentious. Its apparent spread over the last decades is probably still ongoing in several parts of Europe. Here we trace the invasion history of A. vulgaris/lusitanicus by analyzing mitochondrial and nuclear markers in 32 populations covering its entire European distribution. Our results show that there is very little genetic differentiation between different European locations with a main mtDNA haplotype shared by individuals from 20 countries. Most populations in Eastern Europe have fairly low levels of nuclear diversity which is consistent with a very recent arrival of the species there. Genetic diversity of A. vulgaris/lusitanicus is highest in Western and Central European populations, but the common suggestion of an Iberian origin of the invasive slug is not supported by our data. Additionally, there is clear evidence of a strong human impact on the invasion history of this species. It is likely that human activities will also contribute to further range expansion of A. vulgaris/lusitanicus in the future.

Poster session B - GEN 2000

Trancriptome profiling of a key morphological innovation: the propelling fan
of the water walking bug Rhagovelia obesa (52740)

M. Emilia Santos, Abderrahman Khila.

Institute of Functional Genomics of Lyon.

The invasion of new habitats often requires the evolution of key novel traits that facilitate the exploitation of the new environment. The mechanisms and selective forces underlying the emergence of such evolutionary novelties are largely unknown.

In Rhagovelia sp. (water-walking insect) the evolution of an elaborate swimming fan on the mid-legs increases water resistance against leg movements, increasing their propelling function. This trait allowed the Rhagovelia group to conquer and diversify on running water surfaces; a niche inaccessible for other water-walking insects. The genes underlying the fan development are unknown.
Here, we report a comparative analysis of the full transcriptomes of Rhagovelia obesa and Limnoporus dissortis, another water walking insect without propelling fans. We also provide a characterization of gene expression levels between developing mid-legs (with fan) against forelegs and hind-legs (without fan) in R. obesa.

This approach has allowed the identification of a list of genes associated with the evolution of this novel phenotype. Finally, we provide evidence that both co-option of pre-existing genes and lineage specific genes might be involved in the evolution of novel phenotypes. Studying the developmental genetic and adaptive bases of this phenotype will help understand the mechanisms through which novel morphological adaptations emerge under specific environmental pressures.

Poster session B - GEN 2000

## Artificial selection for genital size impacts brain morphology (52783)

**Séverine D. Buechel**, Alexander Kotrschal, Isobel Booksmythe, J. Scott Keogh, Michael D. Jennions, Niclas Kolm.

*Stockholm University; Australian National University.*

The vertebrate brain is one of the most energetically costly organs. Investment into the brain may therefore be prone to trade-offs with other costly traits. Indeed, comparative and experimental studies have shown negative associations between brain size and several other organs. For sexual traits however, evidence remains inconclusive. A recent experimental study even showed positive associations between brain size and male traits; male guppies selected for large brains had higher expression of several sexually selected traits including longer genitalia. Brain size and male sexual traits may be positively associated through at least two mechanisms. First, via selection on a third trait, for instance overall body condition; individuals with larger brains may be better at foraging and thus secure more or better quality food allowing for greater investment in costly sexual traits. Second, a genetic correlation between brain size and sexual traits may be generated through pleiotropy or linkage disequilibrium. Here we test for genetic linkage between brain size and male genitalia length by comparing brain morphology of male mosquitofish (Gambusia holbrooki) artificially selected for long and short genitalia length. We discuss our findings in the light of the many exiting recent advances in brain evolution research.

Poster session B - GEN 2000

## How leaf mimicry of Kallima butterflies evolved? (52794)

**Takao K Suzuki**, Shuichiro Tomita, Hideki Sezutsu.

*National Institute of Agrobiological Sciences.*
Leaf mimicry provides a textbook example of adaptation and is also a historically contentious subject that has spurred criticism of modern evolutionary synthesis. Although Darwin and Wallace (and subsequent evolutionary biologists) argued for the gradual origin of leaf mimesis, the lack of direct experimental evidence has allowed antagonists to produce alternative evolutionary scenarios (e.g. saltation) for leaf mimesis. Here we examine whether the evolutionary process of leaf wing patterns of butterflies (Kallima) was gradual or sudden, and how the evolutionary changes that generated these features accumulated over long time periods. First, comparative morphological analyses indicated that Kallima leaf patterns are decomposed into the homologous pattern elements which 45 closely related species share, suggesting that the pattern elements have been inherited across species. Next, we used Bayesian phylogenetic methods to estimate the ancestral wing patterns, and revealed that the leaf pattern has evolved through several intermediate states from a non-mimetic ancestor. Finally, we estimated the temporal order of character-state changes in the pattern elements by which leaf mimesis evolved. In summary, our study provides the first evidence for gradual evolution of leaf mimicry.

Reference: Suzuki et al. (2014) Gradual and contingent evolutionary emergence of leaf mimicry in butterfly wing patterns. BMC Evol Biol 14:229

# Reproductive isolation between sibling species of seaweeds: the case of two
## Lessonia species along the Chilean coast (52918)

Florence Tellier, Claudia Hurtado, Nicole Badilla, Mauricio Orostica, Natalia Valderrama, Sylvain Faugeron, Myriam Valero.

Facultad de Ciencias, Universidad Catolica de la Santisima Concepcion; Programa de Magister en Ecologia Marina, UCSC (Concepcion, CL); School Ocean Sciences, Bangor University (UK); UMI EBEA 3614, Pontificia Universidad Catolica de Chile (Santiago, CL); UMI EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, UPMC Sorbonne Université (Roscoff FR).

In seaweeds, reproductive isolation among closely-related species has been studied in only a few models. Here we focused on Laminariales, large brown seaweeds (kelps). L. berteroana and L. spicata are cryptic and closely-related species that show a parapatric distribution along the Chilean coast (north and south of 29-30°S), but the overlapping region (29-30°S) is very peculiar as it is composed of successive monospecific patches. Of five contact zones between adjacent patches, four zones showed a complete spatial segregation, and the species range limits correspond to unsuitable areas (200m to 50km long). The last contact zone showed coexistence of species along ~150 m of coastline. Using nuclear markers, we did not find evidence of any interspecific gene flow between patches separated by 1.5 km of unsuitable habitat. This contrasted with the large proportion of hybrids which have been obtained in controlled conditions. Furthermore, the contact zone where both species coexist (currently under study) presented some evidence of temporal isolation (different peaks of reproduction and recruitment). Up to 40% of the fixation discs (i.e. holdfasts) are shared among individuals from distinct species. The role of the different reproductive barriers (intrinsic and extrinsic; prezygotic and postzygotic) will be discussed.
## The total evidence approach with sampled ancestors (52927)

Alexandra Gavryushkina, Tracy Heath, David Welch, Tanja Stadler, **Alexei Drummond**.

*The University of Auckland; Iowa State University; ETH Zurich.*

The evolutionary studies greatly relay on phylogenetic trees. Although there have been developed a number of methods to infer phylogenies there are still problems that require attention. One such problem is the dating of species phylogenies using the fossil evidence. A promising method is the 'total-evidence' approach, where molecular and morphological data of extant and fossil species are jointly used to infer species divergence times and macroevolutionary parameters. However current implementations of the method need to be improved in several aspects. In a Bayesian framework, an important component is the tree prior model which describes the tree branching process. Previous attempts to apply the total-evidence approach have used tree prior models that do not account for the possibility of fossil samples to be direct ancestors of other samples, that is, other fossils or extant species. Recently, Heath et al and Gavryushkina et al applied the fossilized birth-death model that explicitly models the sampling process and naturally allows for sampled ancestors to estimate divergence times based on molecular data and fossil occurrence dates. Here we present a method to analyse morphological and molecular data in a unified Bayesian framework with models that account for sampled direct ancestors. We apply this method to extant penguins and their fossil ancestors.

## Transcriptomic changes characterizing inbreeding depression in a wild population of Alpine ibex (Capra ibex) (52966)

**Kasia Sluzek**, Lukas Keller, Andreas Wagner.

*Institute of Evolutionary Biology and Environmental Studies, University of Zurich.*

When natural populations crash, matings between kin inevitably become more frequent due to shrinkage of the pool of breeding individuals. If the population fails to promptly recover, inbreeding will further accumulate over successive generations at low population size. Inbred individuals experience inflated genome-wide homozygosity leading to the expression of deleterious, recessive alleles and as a consequence, often show depressed fitness. However, the magnitude of inbreeding depression is highly variable amongst individuals of comparable inbreeding coefficients, implying that it is a complex phenomenon not purely determined by global homozygosity levels.

In order to explore the functional underpinnings of inbreeding depression further, we are performing RNASeq on individuals from the ancestral population of Alpine ibex in the Gran Paradiso National Park, Italy.
This population has passed through at least two severe bottlenecks and has previously been shown to exhibit inbreeding depression for a set of fitness-related traits, including body mass, horn length and parasite load. Thus, it constitutes an ideal model for studying the gene expression changes underlying this conservation-relevant syndrome in a natural context.

# Spatial patterns in a human controlled population, the Swedish moose (Alces alces) (52972)

Lovisa Wennerström, **Nils Ryman**.

*Dept. of Zoology, Stockholm University.*

The moose (Alces alces) is the most intensely managed game species in Fennoscandia; approximately one third of the population, c. 16,000 animals, is harvested annually through hunting. Thus, the anthropogenic impact on the species' evolution is high. Despite the obvious risk of human-induced selection and the socio-economic importance of the moose, there are knowledge gaps with respect to its intraspecific diversity and genetic structure. To delineate the current spatial genetic landscape and the population history of the Swedish moose we used allozyme variability from over 20,000 georeferenced moose collected all over Sweden in combination with information from 12 microsatellite loci and mitochondrial DNA sequences. We combined individual-based and traditional statistical approaches with coalescence based simulations. The results indicate a complex history with bottlenecks and recent expansions. We show that the Swedish moose population is separated into two major genetic groups with a transition zone of sharp allelic shifts between them. This genetic structure has been stable for at least 30 years, despite extensive harvest. The divergence is not reflected in the mtDNA variation, however, and we conclude that the population structure of moose occurred after post-glacial immigration to Scandinavia, and is possibly affected by human hunting and harvest induced selection.

# Differentially expressed genes in Anguillicola crassus-infected European eels (53550)

Seraina E. Bracamonte, Michael T. Monaghan, Klaus Knopf.

The occurrence of invasive parasites has increased dramatically in recent years and several of them are implicated in the decline or extinction of their newly acquired host species. The parasitic swim bladder nematode of eels, Anguillicola crassus, has been introduced into the European eel population in the early 1980s and is considered to be one of the factors involved in the decline of its new host. Despite its devastating effect on the host, little is known about the processes affected during host response to an infection with A. crassus. Here we identify pathways that are important during the early stage of an A. crassus infection in European eels. We experimentally infected 3 European eels with A. crassus nematodes and compared the
transcriptome of infected and uninfected individuals for differentially expressed genes at three
days post infection.

The Avian Transcriptome Response to Malaria Infection (53551)

Elin Videvall, Charlie K. Cornwallis, Vaidas Palinauskas, Gediminas Valkiūnas,
Olof Hellgren.

1Department of Biology, Lund University, Lund, Sweden; 1Department of Biology, Lund University, Lund, Sweden; Institute of Ecology, Nature Research Centre, Vilnius, Lithuania; Institute of Ecology, Nature Research Centre, Vilnius, Lithuania; 1Department of Biology, Lund University, Lund, Sweden.

Malaria parasites are highly virulent pathogens which infect a wide range of vertebrates. Despite their importance, the way different hosts control and suppress malaria infections remains poorly understood. With recent developments in next-generation sequencing techniques, however, it is now possible to quantify the response of the entire transcriptome to infections. We experimentally infected Eurasian siskins (Carduelis spinus) with avian malaria parasites (Plasmodium ashfordi), and used high-throughput RNA-sequencing to measure the avian transcriptome in blood collected before infection (day 0), during peak parasitemia (day 21 postinfection), and when parasitemia was decreasing (day 31). We found considerable differences in the transcriptomes of infected and uninfected individuals, with a large number of genes differentially expressed during both peak and decreasing parasitemia stages. These genes were overrepresented among functions involved in the immune system, stress response, cell death regulation, metabolism, and telomerase activity. Comparative analyses of the differentially expressed genes in our study to those found in other hosts of malaria (human and mouse) revealed a set of genes that are potentially involved in highly conserved evolutionary responses to malaria infection. By using RNA-sequencing we gained a more complete view of the host response, and were able to pinpoint not only well-documented host genes but also unannotated genes with clear significance during infection, such as microRNAs. This study shows how the avian blood transcriptome shifts in response to malaria infection, and we believe that it will facilitate further research into the diversity of molecular mechanisms that hosts utilize to fight malaria infections.

The genetic handicap principle: a severely deleterious mutation can be
tolerated if the genome-wide mutation load is sufficiently low (53592)

Konstantin Popadin, Peischl Stephan, Sailani Reza, Letourneau Audrey, Santoni Federico, Garieri Marco, Nikolaev Sergey, Meyer Diogo, Excoffier Laurent, Antonarakis Stylianos E..

*University of Geneva Medical School, Department of Genetic Medicine and Development;*
*University of Lausanne, Center for Integrative Genomics; Institute of Ecology and Evolution,*
Every human genome harbors hundreds of slightly-deleterious mutations. Even though most of these mutations have each a small effect, their cumulative effect (mutation load) could substantially reduce the fitness of an individual. Here we investigate an interaction between a severely deleterious mutation and the mutation load, formulating the genetic handicap principle: an individual bearing a severely deleterious variant (genetic handicap) is viable only if the genome-wide mutation load is sufficiently low. We develop a population-genetic model, which predicts that live-born individuals carrying a handicap mutation (causing, for example, 50-90% probability of miscarriage) show a reduction (5-20%) in their number of slightly-deleterious mutations as compared to controls. To test this prediction, we used data on trisomy of chromosome 21 (T21), a frequent chromosomal abnormality in humans which is associated with high miscarriage rates. Three genetic lines of evidence support the view that live-born T21 individuals have passed through the strong embryonic selection and thus have decreased load of slightly-deleterious mutations. We conclude that the negative fitness consequences of severe mutations such as trisomy can be partially compensated by a reduced genome-wide load of slightly-deleterious mutations abd thus the approach can help to uncover a composition of mutation load.

# Transmission, genome size and the evolution of symbiosis (53702)

Roberta M. Fisher, Henry Lee, Stuart A. West.

Symbiosis between bacteria and their hosts is a potential between-species major evolutionary transition in individuality. Bacterial symbionts are found in a diverse range of hosts, but the degree to which they benefit their hosts varies. A major hypothesis to explain this variation has been transmission route, with vertical transmission of clonal symbionts leading to higher levels of cooperation than horizontal transmission. It has also been suggested that horizontal transmission may be particularly beneficial in changeable or stressful environments. Here, we test the hypothesis that transmission mode and environment determine how much symbionts should benefit their hosts using a phylogenetically controlled comparative analysis of studies measuring host fitness on removal of their symbiont(s). We find (1) vertically transmitted symbionts are more beneficial than horizontally transmitted ones and have smaller genomes, (2) but horizontally transmitted symbionts are relatively more beneficial in stressful versus unstressful environments, (3) that nutritional symbioses are more beneficial to hosts than defensive ones, and (4) mutual dependence leads to a reduction in genome size compared to where there is no dependence. Our results show that to understand the evolution of symbiosis we need to consider multiple aspects of transmission mode, host-symbiont dependence and ecology.
# Fine-scale genetic structure reflects sex-specific dispersal strategies in a population of sociable weavers (51573)

Rene E. van Dijk, Rita Covas, Claire Doutrelant, Claire N. Spottiswoode, Ben J. Hatchwell.

University of Sheffield, UK; CIBIO, Portugal; CEFE-CNRS, France; University of Cambridge, UK.

Dispersal is a critical driver of gene flow, with important consequences for population genetic structure, social interactions and other biological processes. Limited dispersal may result in kin-structured populations in which kin selection may operate, but it may also increase the risk of kin competition and inbreeding. Here, we use a combination of 20 years of data from >6500 birds and molecular genetics to examine dispersal patterns and their consequences for the population genetics of the sociable weaver (Philetairus socius), which exhibits cooperation at various levels of sociality from nuclear family groups to their unique colonial nests. We found that both sexes are philopatric, but that dispersal is female-biased, with females dispersing further and to less-closely related destination colonies than males. This pattern of dispersal is reflected by isolation by distance in terms of genetic relatedness and significant genetic variance among colonies, especially among males. Crucially, significant relatedness extended beyond the level of the colony for both sexes. Such fine-scale population genetic structure has probably played an important role in the evolution of cooperative behaviour in this species, but it may also result in a significant inbreeding risk, against which female-biased dispersal alone is unlikely to be an effective strategy.

# Evolution of parasite interactions and virulence: from within-host growth to epidemiological feedbacks and back again (51695)

Mircea Sofonea, Samuel Alizon, Yannis Michalakis.

Université de Montpellier; CNRS.

Many hosts are infected by several parasite genotypes at a time. Within these coinfected hosts, parasites cooperates through publics goods and compete through spiteful interactions. At between-host level, parasites also compete through transmission so the combinatorial diversity of cotransmission routes complicates the epidemiology and makes it difficult to predict the evolution of virulence. We introduce a new framework to model multiple infections that circumvents and goes beyond the co/super-infection dichotomy owing to explicit within-host dynamics and free cotransmission network. We use analytical solutions and numerical simulations to investigate how within-host dynamics affect the evolution of virulence and reciprocally how epidemiological feedbacks affect the evolution of within-host interactions.
# Decisions of Group Size with Respect to Social Dilemmas and Between-Group Competition (51698)

**Stephen Heap**, Mikael Puurtinen.

*University of Jyväskylä; University of Jyväskylä.*

The interplay of cooperation and conflict drive the evolution of organization and complexity in biological systems, bringing individuals into groups and promoting new levels of individuality. Group size is inherently part of this dynamic, yet studies typically involve small groups of constant size and thus provide only limited scope. Important trade-offs may exist, such that larger groups can have advantages over smaller groups in between-group conflict, yet also experience a weakening of their cooperative bonds due to larger individual incentives to free-ride. Our research uses a public goods game, in which human participants are exposed to a dilemma between individual and cooperative interests. The players can also define their preferred group size, and vote for whether their group competes, cooperates or ignores other groups. We discuss the nature of the trade-offs underlying decisions of group size and the implications that our results have for the emergence of population structures that support cooperation in light of human social evolution and the major evolutionary transitions. Our study thus provides an initial experimental investigation into an expanded realm of inquiry that involves not only the interdependence of cooperation and conflict, but also the self-organized structuring of the population that occurs alongside these principles.

# The Evolution of Antibiotic Resistance in Bacterial Colonies (51791)

**Isabel Frost**, Kevin Foster, Craig MacLean.

*University of Oxford.*

The evolution of antibiotic resistance is one of the major challenges facing society. However, the vast majority of research into antibiotics focuses on solitary cells that are swimming in liquid. In reality, bacteria often live in dense and diverse communities where social interactions are central to their phenotypes. We have been studying how growth in colony biofilms impacts resistance evolution in the pathogen Pseudomonas aeruginosa. Our strain carries a clinical plasmid conferring resistance to streptomycin, which is inactivated intracellularly, and carbenicillin, which is broken down extracellularly and so has more potential for “social” effects where one cell influences the fitness of another. We compete resistant and susceptible strains in varying concentrations of one, or the other, antibiotic. This reveals that susceptible strains can exploit and outcompete resistant strains in the presence of antibiotic, but only for carbenicillin, which has extracellular effects. We also show that this effect depends on the different genotypes being mixed. When different strains make single genotype patches within colonies (high genetic relatedness), the resistant strains are always selected. In sum, we show that antibiotic resistance can be a social trait and this can lead to
# Social microbial immunity: experimental test with Pseudomonas aeruginosa bacterium and lytic bacteriophages (51806)

Ville-Petri Friman, Pierre Moreau, Sandra Andersen, Stephen Diggle.

*Imperial College London; Technical University of Denmark; University of Nottingham.*

The relative benefit of cooperation often increases with the group size. However, group living exposes populations to pathogens and parasites, and as a counter defence, social groups have evolved several altruistic tactics that require cooperation to work efficiently. Here we studied this link with bacteria and their infective parasites, bacteriophages. Pseudomonas aeruginosa bacterium cooperates by secreting and responding to quorum sensing (QS) signal molecules. Thus, we hypothesized that QS genes might be linked to resistance genes against bacteriophages. We found that QS-positive strains reached higher densities in the presence of bacteriophages and that this was due to higher rate of resistance evolution. While non-signaling, QS-negative, cheaters benefited from the presence of QS-positive strain in the presence of phages, non-signaling and non-responding double mutants did not. This result suggests that phage resistance was socially regulated. Moreover, we found that PQS QS-system was especially important in the presence of phage, and that pyoverdin receptors can have a dual function in iron uptake and phage receptor with clinical P. aeruginosa isolates. These results suggest that phage resistance can be socially regulated with P. aeruginosa, and that intra-specific social interactions could also drive trophic level interactions in microbial communities.

# Is vocal similarity used to assess relatedness in cooperative breeders? (51833)

Amy E. Leedale, Ben J. Hatchwell.

*University of Sheffield.*

Animal societies are often composed of relatives, and kin selection is widely invoked to explain cooperation in such groups. Strong selection pressure for effective kin recognition is therefore likely to occur in cooperative species. However, the mechanisms involved are poorly understood. Kin can be discriminated from non-kin using vocalisations in several cooperatively breeding birds, but in some species, individuals can also distinguish between kin of varying relatedness. The mechanism that permits this refined discrimination remains undetermined, but may involve a gradient-based assessment of relatedness through phenotype-matching. We explored how similarity in contact calls may be used to assess kinship in the long-tailed tit Aegithalos caudatus, a species where learned calls provide
information on kinship. By analysing the calls of all adults in a well-studied long-tailed tit population, in which patterns of relatedness are known, we describe how call variation among individuals correlates with relatedness. We discuss whether call similarity could act as a reliable recognition cue for refined discrimination among different degrees of kinship. This could be used to modify helping behaviour to fit Hamilton's rule or as an inbreeding avoidance mechanism. This research contributes to our understanding of recognition systems and how they influence adaptive decisions in social animals.

# Evolution of informed dispersal : the effect of information transmission (51836)

**Ryosuke Iritani.**

*Kyushu University.*

Dispersal, defined as any movement causing gene flow across space, is one of the most fundamental phenomena in ecology and evolution. In particular, informed dispersal, in which individuals use, carry, and transmit information that affects the decision making of dispersal, has recently begun to gather attention both in theory and nature. Because the availability of information exhibits variation, it may generate phenotypic plasticity of dispersal. In the present talk, I introduce several ecological scenarios of information acquisition including vertical transmission, horizontal transmission, individual learning, and so on. I will classify the life-historical scenarios of transmission process/timing that might generate disruptive/stabilizing selection on dispersal, and also predict what scenarios are expected to generate phenotypic plasticity (conditional dispersal) or not (unconditional). I use neighbor-modulated approach to capture the effect of information transmission among relatives in subdivided populations.

# Stable eusociality through maternal manipulation (51872)

**Mauricio González-Forero.**

*University of Lausanne.*

Eusociality involves workers that devote their lives to help. One hypothesis posits that eusociality evolves because workers are manipulated by nestmates into helping. This hypothesis is problematic because manipulated workers could evolve resistance to manipulation, destabilizing eusociality. Resistance can fail to evolve when it is costly, but resistance might be relatively costless if manipulation occurs via queen pheromones, a common way in which worker reproduction is suppressed. Using mathematical models, I find that stable eusociality can evolve from maternal manipulation with costless resistance because of the evolution of maternal reallocation of resources. I study the coevolution of maternal
manipulation, costless resistance, and maternal resource allocation. With an initially limited
ability of offspring to resist manipulation, the mother evolves to reduce her maternal care
toward recipients of help. The mother simultaneously evolves to reallocate the freed resources
into producing offspring that she does not raise and that thus disproportionately benefit from
help. Hence, manipulated workers result helping highly benefiting recipients, rendering
resistance disfavored. The outcome is reproductive division of labor with sterile workers that
are maternally induced and have no incentive to resist. I further find that this process yields
stable eusociality under broader conditions than when manipulation is absent.

Poster session B - GEN 2000

Disgusting or refreshing? Do offspring benefit from feces sharing in the European earwig? (51945)

Maximilian Körner, Janina M.C Diehl, Joel Meunier.

*Department of Evolutionary Biology, Institute of Zoology, Johannes-Gutenberg University Mainz.*

Sociality only evolves when the benefits of group-living outweigh the benefits of solitary life. In family life, it is assumed that parents mostly mediate the benefits of group-living through parental care. However, recent studies revealed resource sharing among mobile siblings, which could play a key role in the early evolution of family life. Here we investigated whether mobile offspring (nymphs) benefit from food sharing through allo-coprophagy in the European earwig, Forficula auricularia. We tested whether access to feces produced by siblings or the mother affects nymph survival in presence/absence of food. We found that access to sibling, but not maternal feces, enhanced offspring survival under food deprivation. We then conducted a food choice experiment to reveal whether nymphs prefer food to feces, and if they discriminate between feces produced by related and unrelated nymphs and mothers. We found that offspring preferred food over feces while still consuming some feces in presence of food. Without food, however, nymphs showed no preference between sibling or mother feces. Overall, our results show defecation having possibly meaningful effects on group living by mediating beneficial interactions. More generally, they show that feces release and sharing possibly play an important role in the evolution of sociality.

Poster session B - GEN 2000

Cooperative bacteria in stationary phase are immune to cheating (51951)

Melanie Ghoul, Stuart West, Ashleigh Griffin.

*University of Oxford.*

Microbial cells rely on cooperative behaviours that can breakdown as a result of exploitation
by cheats. Despite cheats invading, cooperation dominates microbial life. A continuing
challenge is to determine how natural cooperative populations resist cheating and to what
extent experimental studies give insight into microbial life outside of laboratory cultures. First we illustrate the importance of defining cheating correctly in evolution studies of social behaviours. We show that whether a strain is a cheat depends on the costs and benefits associated with the social and abiotic environment and not the absolute expression of a cooperative trait. In nature bacteria exist as established populations in a non-growing state similar to the stationary phase of laboratory cultures. A limitation with experimental bacterial studies is that cheating is often tested for in competition assays initiated with cooperator populations at a low density - in lag phase. Here, we use the production of pyoverdin, an iron scavenging siderophore, as a public good in the bacteria Pseudomonas aeruginosa, to test how the growth stage of a cooperative population affects a cheat's invasive ability. We show that a strain's ability to cheat correlates with the rates of pyoverdin production, which varies with the bacterial growth stage.

## Eco-evolutionary dynamics of social dilemmas (52059)

**Chaitanya Gokhale**, Christoph Hauert.

*New Zealand Institute for Advanced Study, Massey University; Department of Mathematics, University of British Columbia.*

Social dilemmas are an integral part of social interactions ranging from microbial populations to human societies. Cooperative interactions such as the secretion of expensive extracellular products or blood donations, are costly to the actor but provide potentially vital benefits to recipients. Both costs and benefits often depend non-linearly on the number and types of individuals involved – as captured by idioms such as 'too many cooks spoil the broth' where additional contributions are discounted, or 'two heads are better than one' where cooperators can synergistically enhance the group benefit. Interaction group sizes often depend on the size of the population and hence on ecological processes. This results in feedback mechanisms between ecological and evolutionary processes, which jointly affect and determine the evolutionary trajectory. Only recently became such combined processes experimentally tractable in microbial social dilemmas. Here we analyse non-linear social dilemmas in eco-evolutionary settings where the population fluctuates in size and the environment can change over time. We find that combining these traditionally independently studied processes has the potential to routinely reveal highly complex dynamics, which are infrequent when studied in isolation but possibly quite common in nature. One particularly interesting outcome is the evolutionary feasibility and maintenance of cooperation at high densities in ecologically fluctuating populations.

## The co-evolution of social institutions, demography, and large-scale human cooperation (52070)

**Simon Powers**, Laurent Lehmann.
Human cooperation is typically coordinated by institutions, which determine the outcome structure of the social interactions individuals engage in. Explaining the Neolithic transition from small- to large-scale societies involves understanding how these institutions co-evolve with demography. Yet nearly all previous evolutionary models have assumed that social interactions, such as cooperation and punishment, are carried out in an entirely uncoordinated and unilateral manner. Consequently, very little work has studied the evolutionary origin of social institutions, and none has considered how they co-evolve with aspects of human demography such as carrying capacity. We address this using a demographically explicit model of institution formation in a patch-structured population. Each patch supports both social and asocial niches. Social individuals create an institution, at a cost to themselves, by negotiating how much of the costly public good provided by cooperators is invested into sanctioning defectors. The remainder of their public good is invested in technology that increases carrying capacity, such as irrigation systems. We show that social individuals can invade a population of asocials, and form institutions that support high levels of cooperation. We then demonstrate conditions where the co-evolution of cooperation, institutions, and carrying capacity creates a transition from small- to large-scale social groups.

# Family living - an overlooked social system in the evolutionary history of cooperation (52159)

Szymon Drobniak, Michael Griesser.

Cooperative breeding represents one of the major challenges in evolutionary biology. In spite of understanding its ultimate causes we still lack proper understanding of how a prerequisite of cooperation - namely delayed post-natal dispersal - evolved. Here we suggest a novel approach by considering the third social system category, expanding currently bi-categorical classification into cooperatively and non-cooperatively breeding species. Using a large sample of extant species we demonstrate that family living, i.e. delayed post-natal dispersal of offspring without further reproductive cooperation, represents a distinct social system that should not be merged together with non-family living species. Family-living species differ substantially from non-family living ones in terms of their life history, i.e. they exhibit much lower levels of initial reproductive investment. Using this life-history trait we derive a new classification, based on the time the offspring stays with their parents beyond nutritional independence, which successfully classify bird species into family and non-family living ones. This new approach will substantially expand our understanding of how delayed dispersal evolved. Moreover, since reproductive cooperation occurs almost exclusively in families, family living is likely to represent an important intermediate state in the evolution of cooperation.
# The evolution of anti-social rewarding and its counter-measures in public goods games (52160)

Miguel dos Santos.

*Department of Ecology and Evolution, University of Lausanne.*

Cooperation in joint enterprises breaks down when self-interests are in conflict with collective benefits, causing a tragedy of the commons. In such dilemmas, the possibility for contributors to invest in pool-reward funds which will be shared exclusively among contributors, can be powerful for averting the tragedy, as long as the second-order dilemma (withdrawing contribution to reward funds) can be overcome, e.g. with second-order sanctions. In human societies however, wrong-doers can also pool their effort to reward each other, and profit from productive joint enterprises of their own. The present research reveals the vulnerability of pool-rewards to the presence of reward funds raised by defectors and shared among them. Such ‘anti-social rewarding’ causes a cooperation breakdown, even when second-order sanctions are possible. Escaping this social trap requires the additional condition that coalitions of defectors fare poorly compared to pro-socials, with either better rewarding abilities for the latter, or reward funds that are contingent upon the public good produced beforehand, allowing groups of contributors to invest more in reward funds than groups of defectors. Future experiments on pool-reward funds should allow anti-social rewarding in order to fully understand how positive incentive mechanisms can enhance human cooperation in collective action dilemmas.

Poster session B - GEN 2000

# Cooperating to Exclude Competitors in Natural Bacterial Populations (52174)

John Bruce, Stuart West, Ashleigh Griffin.

*University of Oxford.*

All bacteria produce antagonistic compounds, such as bacteriocins, which are important determinants of intraspecific competition. Both theory and experimental studies have shown that production of these toxins is important for the invasion and defence of niches, as well as providing a mechanism to maintain diversity. However, the relevance of antagonistic behaviours to the diversity and distribution of strains in natural bacterial populations is unknown. Here, we sampled and genetically characterized natural populations of Pseudomonas fluorescens from soil at multiple sites in a local park and constructed a network of antagonistic interactions between strains. We find that genetically diverse strains coexist at very local, centimetre, scales and demonstrate that antagonism is attenuated locally, within-sites, and more prevalent between-sites. These results suggest that these genetically diverse populations of P.fluorescens are adapted to their local social environment: they are resistant to an array of locally produced toxins. This may be the result of limited dispersal in local populations, or alternatively, antagonistic interactions may reinforce boundaries between populations and deter invasion by conspecifics. This raises both theoretical and empirical questions concerning how antagonistic traits, through their influence on population structure, will coevolve with cooperative traits.
# Evolution of an artificial ecosystem (52239)

## Yu Liu.

Uppsala University.

We made an agent-based model with the purpose to study that why some specific interactions or food webs would emerge, what the most important underlying mechanism is, whether there are general patterns for an ecosystem to evolve, etc.

In the model, the system consists of ‘microbes’ and ‘substances’. Each kind of microbes digests and excretes specific substances (a simple rule decides what substances it excretes according to what it digests). The metabolic path is recorded in their ‘genes’ which could mutate. Reproduction happens when microbes have enough food to digest, while death happens when they starve.

There are some primary results till now. Firstly, there are patterns from the simulations which could be found in the real world, totally emerging from the very simple model, even though we did not assume any priori fitness functions. Secondly, the artificial system seems to have serial stages, like a young forest grows to an old forest. Thirdly, since we know how each individual behaves, we could explain various patterns (population structure, trophic level, etc.) of the artificial ecosystem from the individual level.

# Natural and experimentally induced queen succession in the tropical social wasp Ropalidia marginata (52252)

Paromita Saha, M. C. Shilpa, Sruthi Unnikrishnan, Shantanu Shukla, Souvik Mandal, Anjan Nandi, Aniruddha Mitra, Raghavendra Gadagkar.

Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India.; Evolution Génomes Comportement Ecologie, Centre National de la Recherche Scientifique, France.

Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We study queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioural strategies involved in the resolution of this conflict. Experimental queen removal always results in one worker becoming hyper-aggressive and taking over the colony as its next queen. Here we show that even during natural queen turn-over, one and only one worker becomes hyper-aggressive and takes over as the next queen, without any scramble competition. Unlike in the case of experimental queen removal however, during natural queen turn-over, aggression of the successor may begin before the loss of the old queen and may decline more rapidly. As might be expected, the successor begins to lay eggs sooner after a natural queen
turn-over as compared to experimental queen removal. Because queen succession is expected
to be more prevalent in tropical perennial species, we expect natural selection to have
favoured such an orderly queen succession without scramble competition.

Poster session B - GEN 2000

Cooperation mediates density-dependent dispersal and colonization efficiency
in a ciliate (52280)

Staffan Jacob, Priscilla Wehi, Alexis Chaine, Delphine Legrand, Nicolas Schtickzelle, Michele Huet, Jean Clobert.

CNRS Moulis; Landcare Research Manaaki Whenua, New Zealand; Earth and Life Institute
& Biodiversity Research Centre, Belgium.

Theory predicts that low dispersal is required for the evolution of cooperation because it maintains high within-groups relatedness. However, limited dispersal also increases kin competition and can therefore negate the benefits of cooperation. Theoretical work has suggested that conditional dispersal, when individuals can adjust their dispersal decisions to the local context, might resolve this paradox. We tested the hypothesis that density-dependent dispersal decisions should differ between six genotypes of the unicellular Tetrahymena thermophila differing in cooperation strategy. Furthermore, we investigated whether cooperation strategy affects post-dispersal colonization efficiency from single founder cells or several cells (akin to group dispersal). We found that density-dependent dispersal decisions and dispersers' phenotype differed between genotypes' cooperation level. Cooperative lines decreased dispersal rate with density, whereas dispersal rate in low cooperative lines was low at extreme densities and high at intermediate densities. Moreover, colonization efficiency after dispersal of cooperative genotypes was low for single founder cells compared to less cooperative lines, and as efficient as less cooperative lines when colonization occurred from several cells. Thus, kin cooperation during transience and/or settlement may exist for high cooperative lines. Our results demonstrate that cooperation strategy governs both density-dependent dispersal decisions and the subsequent colonization success.

Poster session B - GEN 2000

The Evolution of Cooperation through Genetic Niche Hiking (52330)

Sarah Hammarlund, Brian Connelly, Katie Dickinson, Benjamin Kerr.

University of Washington; University of Oxford.

Cooperation is evolutionarily paradoxical. When individuals pay a cost to benefit others, cooperators are at a competitive disadvantage relative to non-cooperators (“defectors”). Most solutions to this paradox involve a scenario where cooperators disproportionately benefit from cooperation (e.g., via interactions with kin). Here we model the evolution of cooperation under circumstances where such positive assortment occurs but is not sufficient to ensure
cooperator success. Our scenario begins with an exogenous stress, where stress tolerance is completely unrelated to cooperation. This stress (1) thins the population, after which growth can lead to clustering of like types, and (2) creates opportunities for adaptation to the stress itself. In structured, adapting populations, cooperator-rich populations reach larger population sizes; consequently, cooperative lineages experience more mutational opportunities to adapt to the stressful conditions, which allows cooperators to competitively displace defectors. Such displacement can occur even as the population structure erodes. In analogy with genetic hitchhiking, we call this process "genetic niche hiking," where an otherwise deleterious allele for cooperation can increase in frequency due to an association with the "niche" it creates. We explore this process in detail using an agent-based computational model and discuss genetic niche hiking in the context of exoenzyme production in bacteria.

Poster session B - GEN 2000

# Social evolution and antibiotic resistance in Pseudomonas aeruginosa infections (52350)

David Crosse, Melanie Ghoul, Ashleigh Griffin.

*University of Oxford.*

Antibiotic resistance is a global health crisis. As pathogenic bacteria are social organisms, social evolutionary theory needs to be applied to this problem. Beta-lactam antibiotics (a major class which includes the penicillins) are often resisted by beta-lactamase, an extracellular enzyme. Beta-lactamase is potentially a public good: cooperative producers could therefore be vulnerable to exploitation by non-producing cheats. Pseudomonas aeruginosa is an opportunistic pathogen that uses beta-lactamase for resistance. It causes chronic lung infections in cystic fibrosis (CF) patients, where it is the primary cause of morbidity and mortality. In this study we assay beta-lactamase production in sequential isolates from 17 CF patients to look for potential cheats, and we test whether high beta-lactamase producers can cross-protect a coexisting non-producer. As non-producers are themselves vulnerable to antibiotics, their maintenance in a bacterial population would be of considerable clinical significance.

Poster session B - GEN 2000

# Brood discrimination in the ant Formica exsecta (52449)

Unni Pulliainen, Nick Bos, Patrizia d'Ettorre, Liselotte Sundström.

*University of Helsinki; Université Paris 13.*

In social insects, the ability to recognize and discriminate nestmates from non nestmates plays an important part in maintaining colony integrity and protecting the colony and its resources from unrelated intruders and social parasites. Typical colony intruders are adult individuals, and thus recognition among adults is highly developed and precise. However, whether ants
can recognize and discriminate brood of different origins is less clear. From a fitness point of
view it would naturally be beneficial for a colony to accept nest mate brood. Accepting alien
worker destined brood, especially pupae, might not be harmful either, and it might even be
beneficial, as in some cases alien workers, adopted as brood, successfully integrate into
adoptive colonies. However, accepting alien sexual brood should be avoided as these
individuals may use colony resources without contributing to the colony, and instead act as
social parasites. We investigated whether worker ants are efficient in discriminating brood,
and whether the discrimination rules differ among brood of different castes. We answer these
questions using behavioural assays coupled with chemical analysis in the ant Formica exsecta.

Facilitation and kin selection in a Patagonian dominant tree (52490)

Irène Till-Bottraud, Alex Fajardo, Cristain Torres.

Univ. Grenoble Alpes, Laboratoire d'Ecologie Alpine (LECA), F-38000 Grenoble, France;
CNRS, LECA, CNRS F-38000 Grenoble, France; Centro de Investigación en Ecosistemas de
la Patagonia (CIEP) Conicyt-Regional R10C1003, Universidad; Laboratorio de Genómica y
Biodiversidad, Departamento de Ciencias Básicas, Universidad del Bío Bío, .

In plant ecological theory, beneficial interactions occur mostly under stressful conditions (facilitation; in the context of the “stress gradient hypothesis”). Facilitation is commonly described as an interspecific interaction in which at least one of the species benefits from the interaction. Among individuals of the same species and the same cohort, the interaction is reciprocal and all individuals benefit from the interaction (cooperation). We studied one such case of facilitation in Nothofagus pumilio, a dominant tree species in Patagonia. The edge of post-fire even-aged second-growth forests is composed of merged trees. We showed that seedlings growing in clusters at the edge of the forest facilitate each other (greater survival than alone) by sheltering each other from the strong winds. Merging of the seedlings occur at a later stage. We found that merged stems were more closely related than on average in the population. We also showed, in an experiment where seedlings were planted in clusters, that mortality over 7 years lead to significantly higher than average relatedness within the clusters, indicating selection for kin individuals. This situation is thus an example of kin cooperation in plants, with facilitation being a prerequisite for kin selection.

A dynamic model of reproductive decisions in primitively eusocial insects
(52529)

Piret Avila, Lutz Fromhage.

University of Jyväskylä.
Cooperative breeding has arisen numerous times in the Hymenoptera, but the role of time-
and context-dependent decision rules in this context is still incompletely understood. To study
this topic, we developed a stochastic dynamic game model of the behaviour of a seasonal
cooperatively breeding insect with alloparental care, in which dispersing females must decide
between founding a nest or joining an existing nest as a helper. We assume that the dominant
female in a nest does all the reproduction; that establishing a nest takes time and effort before
any sexual offspring can be produced; and that helpers can inherit the nest if the dominant
dies. We assess the relative importance of indirect and direct fitness effects in the decision
making process and the degree to which evolved helping behaviour is mutualistic or altruistic.
We also study the degree to which environmental constraints, effort of nest establishment and
average within-group relatedness affect optimal decisions of females and expected group size.

Poster session B - GEN 2000

Queen signal evolution in social Hymenoptera (52698)

Jelle van Zweden.

KU Leuven.

Social Hymenoptera have long been a model to study the evolution of cooperation. They are characterized by a reproductive division of labour, whereby queens perform most of the reproduction and workers help to raise offspring. Queen pheromones, which signal the presence of a fertile queen and reduce reproduction in the workers, are thought to play a key role in regulating this altruistic system. Progress in the study of queen pheromones has been slow, since very few had been identified up until a few years ago. Their evolutionary history, therefore, remained unknown. Recently, however, we identified sterility-inducing queen pheromones in several species of ant, wasp and bee. Moreover, by synthesizing existing data of compounds that characterize female fertility in species of social Hymenoptera, we find that these are strikingly conserved in lineages of Lasius ants and Vespinae wasps, as well as across at least three independent origins of eusociality. Wasps, ants and some bees all appear to use non-volatile, saturated hydrocarbons to advertise fertility and reduce worker reproduction. These results suggest that queen signals follow very similar evolutionary trajectories from solitary ancestors, and argue against rapid evolution that would result from queen-worker arms races ensuing from manipulative queen control.

Poster session B - GEN 2000

Does cooperation mean kinship in spatially discrete nests within an ant
colony? (52707)

Duncan Procter, Michael Hofreiter, Joan Cottrell, Kevin Watts, Elva Robinson.

University of York; Universitat Potsdam; Forest Research.
Ant colonies are often one of the first examples people give of kin selection in action, with the classical description of a colony in one nest (monodomy) with highly related workers and a single queen (monogyny). However this is very often not the case. As well as the well-studied phenomenon of multiple queens in each nest (polygyny), colonies can be split between spatially discrete nests (polydomy). Polydomous colonies are defined by social connections between discrete nests, and in many species multiple colonies live side by side. This begs the question, what causes these polydomous colonies to keep a social connection with some nests and not others? Is this colony really a good example of kin selection after all or is it merely two nests cooperating for some other reason? The red wood ant Formica lugubris is polygyne and polydomous in the UK. Using 20 triplets of nests, two of which were from the same colony and the third from a neighbouring separate colony we used analysis of worker movement, resource transfer and relatedness of nests to put this definition of a polydomous colony into an evolutionary perspective and ask whether kinship does determine cooperation in this situation.

# The rise and fall of cooperative breeding in birds – the role of life-history and ecology for evolutionary transitions to and from cooperative breeding (52795)

Michael Griesser, Szymon M Drobniak, Shinichi Nakagawa.

*University of Zurich; University of Otago.*

Understanding cooperation in animal societies is a key question of evolutionary biology. Yet theory and comparative studies so far contrasted cooperative breeders with non-cooperative breeders. This approach neglects that non-cooperative breeders are a heterogeneous group encompassing both non-family and family living species, however, cooperation primarily takes place within families. Using a phyla-wide dataset in birds, we show that evolutionary transitions occur from pair-living to family living, and from there to cooperative breeding, in both directions along this axis. Moreover, the transition patterns differ across different lineages, where life-history parameters and ecology play a key role in influencing whether lineages remain asocial whether they evolve family living, or whether they also evolve cooperative breeding. For example, most precocial linages evolve family living but never evolve cooperative breeding, confirming that particularly altrical species benefit from cooperative breeding. Overall, our results provide an important conceptual advancement, showing that understanding family living might be crucial to resolve the evolution of cooperative breeding.

# Resource competition and population structure makes social learning models more biologically relevant (52855)

Marco Smolla, Tobias Galla, Tucker Gilman, Susanne Shultz.
*Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester; Complex Systems and Statistical Physics Group, School of Physics and Astro, University of Manchester.*

The success of humans in colonising virtually every terrestrial habitat is based on cumulative culture. Its fundamental mechanism is social learning (gaining information by interacting with or observing others), which is widespread in the animal kingdom. A recent social learning strategies tournament (Rendell et al., 2010, Science) found that the most competitive strategies almost entirely rely on social learning; a surprising result, which contradicts empirical findings that show most animals opt for asocially and not socially acquired information.

By using an agent-based model relying on resource competition and population structure, we can show that environmental conditions, such as strength of competition, number of resources, environmental stability, evenness of resource values, and network properties strongly influence the success of social learning.

Our model is more biologically relevant than earlier models that rely on arbitrary learning costs and neglect resource competition, which is omnipresent in nature. We believe our model will not only help us to better understand the evolution of social learning, but also shed light on the evolution of cumulative culture in humans.

Poster session B - GEN 2000

# Comparison of Public and Private Partner Selection Models in Cooperation and Coordination Games (52881)

**Pedro Mariano**, Davide Nunes, Luís Correia.

*BioISI - Dep. de Informática, Faculdade de Ciências, Universidade de Lisboa.*

We have been investigating how public and private partner selection models promote cooperation and diversity in a population of evolving agents using well known games such as Prisoner's Dilemma, Stag Hunt, Snowdrift, Public Good Provision, Centipede, Ultimatum, Battle of Sexes, and Give-and-Take. Our models are generic in the sense that they only use the payoff obtained by the selecting agent to update its partner selection policy.

Both partner selection models are able to promote cooperation compared to random partner selection. As for diversity in coordination games, only the public partner selection had partial success. We have observed groups of agents with different ways to play the game during many iterations of the evolutionary algorithm, but in the long run, only one strategy profile prevails.

In ongoing work we are investigating other ways to promote diversity in cooperation and coordination games. One avenue of research consists in having in the chromosome all the parameters of the partner selection models. In previous work, some of the parameters were externally defined.

P. Mariano and L. Correia. Partner selection delays extinction in cooperative and coordination dilemmas. In F. Grimaldo and E. Norling, editors,
# A selfish genetic element influences sperm precedence patterns in house mice (51706)

Andreas Sutter, Anna K. Lindholm.

*University of Zurich.*

Multiple mating by females is taxonomically wide-spread, which extends male-male competition beyond pre-copulatory contest. Sperm precedence patterns are typically species-specific, and males are predicted to tailor their investment according to whether they mate in the favoured or disfavoured role. Selfish genetic elements (SGEs) that favour their own transmission at the cost of the entire organism often target male gametogenesis, with potential consequences on optimal male reproductive strategies.

The t haplotype in house mice is the best-known SGE in a vertebrate. It exhibits strong transmission ratio distortion in males by influencing spermatogenesis and male carriers are strongly disadvantaged in sperm competition compared to wild type males. Here, we investigated sperm precedence patterns in sperm competition trials involving males with a t haplotype. We found that sperm precedence patterns depended on whether t males were involved in sperm competition. Competition between t carriers resulted in a reversal of the species-typical first male precedence and the optimal timing of ejaculation was different for t heterozygous and wild type males. Nevertheless, males did not tailor their copulatory behaviour depending on their t haplotype status.

We discuss these findings in the light of genomic conflict and constraints arising from the genetic control of copulatory behaviour.

# Prezygotic segregation distortion in female and male zebra finches (Taeniopygia guttata (51707))

Ulrich Knief, Holger Schielzeth, Hans Ellegren, Bart Kempenaers, Wolfgang Forstmeier.

Max Planck Institute for Ornithology, Department of Behavioural Ecology and Evolutionary Genetics; Bielefeld University, Department of Evolutionary Biology; Uppsala University, Department of Evolutionary Biology.

At least three processes can lead to an apparent departure from fair Mendelian segregation: (early) viability selection, biased gene conversion and segregation distortion. Here we conduct a genome-wide scan for transmission distortion in a captive population of zebra finches (Taeniopygia guttata) using 1,302 single nucleotide polymorphisms followed by confirmatory analyses on independent samples from the same population. In the genome scan we found