cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5683/sp2/fjoude
title: Data from: Evolution of haploid selection in predominantly diploid organisms

description: AbstractDiploid organisms manipulate the extent to which their haploid gametes experience selection. Animals typically produce sperm with a diploid complement of most proteins and RNA, limiting selection on the haploid genotype. Plants, however, exhibit extensive expression in pollen, with actively transcribed haploid genomes. Here we analyze models that track the evolution of genes that modify the strength of haploid selection to predict when evolution intensifies and when it dampens the “selective arena” within which male gametes compete for fertilization. Considering deleterious mutations, evolution leads diploid mothers to strengthen selection among haploid sperm/pollen, because this reduces the mutation load inherited by their diploid offspring. If, however, selection acts in opposite directions in haploids and diploids (“ploidally antagonistic selection”), mothers evolve to reduce haploid selection to avoid selectively amplifying alleles harmful to their offspring. Consequently, with maternal control, selection in the haploid phase either is maximized or reaches an intermediate state, depending on the deleterious mutation rate relative to the extent of ploidally antagonistic selection. By contrast, evolution generally leads diploid fathers to mask mutations in their gametes to the maximum extent possible, whenever masking (e.g., through transcript sharing) increases the average fitness of a father’s gametes. We discuss the implications of this maternal–paternal conflict over the extent of haploid selection and describe empirical studies needed to refine our understanding of haploid selection among seemingly diploid organisms.
DOI: 10.5683/sp2/lalfbd
title: Data from: Evolution of haploid–diploid life cycles when haploid and diploid fitnesses are not equal

description: AbstractMany organisms spend a significant portion of their life cycle as haploids and as diploids (a haploid–diploid life cycle). However, the evolutionary processes that could maintain this sort of life cycle are unclear. Most previous models of ploidy evolution have assumed that the fitness effects of new mutations are equal in haploids and homozygous diploids, however, this equivalency is not supported by empirical data. With different mutational effects, the overall (intrinsic) fitness of a haploid would not be equal to that of a diploid after a series of substitution events. Intrinsic fitness differences between haploids and diploids can also arise directly, for example because diploids tend to have larger cell sizes than haploids. Here, we incorporate intrinsic fitness differences into genetic models for the evolution of time spent in the haploid versus diploid phases, in which ploidy affects whether new mutations are masked. Life-cycle evolution can be affected by intrinsic fitness differences between phases, the masking of mutations, or a combination of both. We find parameter ranges where these two selective forces act and show that the balance between them can favor convergence on a haploid–diploid life cycle, which is not observed in the absence of intrinsic fitness differences.
DOI: 10.5683/sp2/ezo3ip
title: Data from: Evolution of invasiveness by genetic accommodation

description: AbstractInvasion success of species introduced to novel environments may be facilitated by adaptive evolution and by phenotypic plasticity. Here we investigate the independent and joint contribution of both mechanisms as drivers of invasiveness in the perennial sunflower Helianthus tuberosus. We show that invasive genotypes have multiple origins, and that invasive spread was facilitated by the repeated evolution of extreme values in a single trait, clonality. In line with genetic accommodation theory, we establish that this evolutionary transition occurred by refining a preexisting plastic response of clonality to water availability. Further, we demonstrate that under the non-drought conditions typically experienced by this plant in its introduced range, invasive spread is mediated by hybrid vigor and/or two major additive-effect loci, and that these mechanisms are complementary. Thus, in H. tuberosus, evolution of invasiveness was facilitated by phenotypic plasticity, and involved the use of multiple genetic solutions to achieve the same invasiveness trait.
DOI: 10.5683/sp2/hgldfk
title: Data from: Evolution of movement rate increases the effectiveness of marine reserves for the conservation of pelagic fishes

description: AbstractCurrent debates about the efficacy of no-take marine reserves (MR) in protecting large pelagic fish such as tuna and sharks have usually not considered the evolutionary dimension of this issue, which emerges because the propensity to swim away from a given place, like any other biological trait, will probably vary in a heritable fashion among individuals. Here, based on spatially-explicit simulations, we investigated whether selection to remain in MRs to avoid higher fishing mortality can lead to the evolution of more philopatric fish. Our simulations, which covered a range of life histories among tuna species (skipjack tuna vs. Atlantic Bluefin tuna) and shark species (great white sharks vs. spiny dogfish) suggested that MRs were most effective at maintaining viable population sizes when movement distances were lowest. Decreased movement rate evolved following the establishment of marine reserves, and this evolution occurred more rapidly with higher fishing pressure. Evolutionary reductions in movement rate led to increases in within-reserve population sizes over the course of the 50 years following MR establishment, although this varied among life-histories, with skipjack responding fastest and great white sharks slowest. Our results suggest the evolution of decreased movement can augment the efficacy of marine reserves, especially for species, such as skipjack tuna, with relatively short generation times. Even when movement rates did not evolve substantially over 50 years (e.g., given long generation times or little heritable variation), marine reserves were an effective tool for the conservation of fish populations when mean movement rates were low or MRs were large.
DOI: 10.5683/sp2/vfcnj6
title: Data from: Evolutionarily stable sex ratios and mutation load

description: AbstractFrequency-dependent selection should drive dioecious populations toward a 1:1 sex ratio, but biased sex ratios are widespread, especially among plants with sex chromosomes. Here, we develop population genetic models to investigate the relationships between evolutionarily stable sex ratios, haploid selection, and deleterious mutation load. We confirm that when haploid selection acts only on the relative fitness of X and Y-bearing pollen and the sex ratio is controlled by the maternal genotype, seed sex ratios evolve toward 1:1. When we also consider haploid selection acting on deleterious mutations, however, we find that biased sex ratios can be stably maintained, reflecting a balance between the advantages of purging deleterious mutations via haploid selection, and the disadvantages of haploid selection on the sex ratio. Our results provide a plausible evolutionary explanation for biased sex ratios in dioecious plants, given the extensive gene expression that occurs across plant genomes at the haploid stage.
DOI: 10.5683/sp2/fpt7l1
title: Data from: Evolutionary origin of highly repetitive plastid genomes within the clover genus (Trifolium)

description: AbstractBackground: Some clover species, particularly Trifolium subterraneum, have previously been reported to have highly unusual plastomes, relative to closely related legumes, enlarged with many duplications, gene losses and the presence of DNA unique to Trifolium, which may represent horizontal transfer. In order to pinpoint the evolutionary origin of this phenomenon within the genus Trifolium, we sequenced and assembled the plastomes of eight additional Trifolium species widely sampled from across the genus. Results: The Trifolium plastomes fell into two groups: those of Trifolium boissieri, T. strictum and T. glanduliferum (representing subgenus Chronosemium and subg. Trifolium section Paramesus) were tractable, assembled readily and were not unusual in the general context of Fabeae plastomes. The other Trifolium species (“core Trifolium”) proved refractory to assembly mainly because of numerous short duplications. These species form a single clade, which we call the “refractory clade” (comprising subg, Trifolium sections Lupinaster, Trifolium, Trichocephalum, Vesicastrum and Trifoliastrum). The characteristics of the refractory clade are the presence of numerous short duplications and 7-15% longer genomes than the tractable species. Molecular dating estimates that the origin of the most recent common ancestor (MRCA) of the refractory clade is approximately 13.1 million years ago (MYA). This is considerably younger than the estimated MRCA ages of Trifolium (c. 18.6 MYA) andTrifolium subg. Trifolium (16.1 MYA). Conclusions: We conclude that the unusual repetitive plastome type previously characterized in Trifolium subterraneum had a single origin within Trifolium and is characteristic of most (but not all) species of subgenus Trifolium. It appears that an ancestral plastome within Trifolium underwent an evolutionary change resulting in plastomes that either actively promoted, were permissive to, or were unable to control, duplications within the genome. The precise mechanism of this important change in the mode and tempo of plastome evolution deserves further investigation.
DOI: 10.5683/sp2/wud3cj
title: Data from: Evolutionary potential in the Alpine: trait heritabilities and performance variation of the dwarf willow Salix herbacea from different elevations and microhabitats

description: AbstractAlpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological traits, leaf size, and performance traits in natural populations of the long-lived alpine dwarf shrub Salix herbacea using relatedness estimates inferred from SSR (Simple Sequence Repeat) markers. Salix herbacea occurs in early- and late-snowmelt microhabitats (ridges and snowbeds), and we assessed how performance consequences of phenological traits and leaf size differ between these microhabitats in order to infer potential for evolutionary responses. Salix herbacea showed low, but significant, heritabilities of leaf size, clonal and sexual reproduction, and moderate heritabilities of phenological traits. In both microhabitats, we found that larger leaves, longer intervals between snowmelt and leaf expansion, and longer GDD (growing-degree days) until leaf expansion resulted in a stronger increase in the number of stems (clonal reproduction). In snowbeds, clonal reproduction increased with a shorter GDD until flowering, while the opposite was found on ridges. Furthermore, the proportion of flowering stems increased with GDD until flowering in both microhabitats. Our results suggest that the presence of significant heritable variation in morphology and phenology might help S. herbacea to adapt to changing environmental conditions. However, it remains to be seen if the rate of such an evolutionary response can keep pace with the rapid rate of climate change.
DOI: 10.5683/sp2/0al2t1
title: Data from: Experimental confirmation that body size determines mate preference via phenotype matching in a stickleback species pair

description: AbstractMate choice by phenotype matching, whereby individuals prefer a mate whose phenotype is similar to their own, should facilitate speciation with gene flow. This is because the genes that control mate signal (the phenotype being matched) also determine the preferred mate signal (‘mate preference’). Speciation is made even easier if phenotype matching is based on a trait under divergent natural selection. In this case, assortative mating should readily evolve as a by-product of divergent selection on the trait. Previous observational studies of assortative mating between sympatric, hybridizing threespine stickleback species (Gasterosteus aculeatus complex) suggested that phenotype matching might occur by body size, a trait under divergent natural selection. To test this we used experimental manipulation of body size to rule out the effects of confounding variables. We found that size-manipulated benthic and limnetic stickleback females prefer mates whose body size more closely matches their own. It is thus likely that assortative mating by phenotype matching has facilitated the origin and persistence of benthic and limnetic threespine sticklebacks in the face of gene flow.
DOI: 10.5683/sp2/omopyk
title: Data from: Exploring preferences for variable delays over fixed delays to high-value food rewards as a model of food-seeking behaviours in humans

description: AbstractForaging and operant models suggest that animals will tolerate uncertainty or risk to obtain food quickly. In modern food environments, sustained access to quick energy-dense foods can promote weight gain. Here, we used a discrete-choice procedure to examine peoples' decisions about when next to eat high-value, palatable food rewards, probabilistically delivered immediately or following longer delays. In Experiment 1, moderately hungry young females showed consistent preferences for a variable delay option that delivered food rewards immediately or following long delays over a fixed delay option that delivered the same rewards following intermediate delays. These preferences were stronger in females with higher BMIs compared with lower BMIs, suggesting that quick food can enhance the value of uncertain or ‘risky’ food-seeking strategies in individuals vulnerable to future weight gain. In Experiment 2, prior exposure to a subtle and not easily identifiable food aroma increased selections of the variable delay option following delayed food rewards in a mixed sample of male and female adults, providing preliminary evidence that food cues can sustain uncertain food-seeking strategies. These data highlight a working hypothesis that the rapid delivery and consumption of food rewards, and food cues, can increase risk-tolerance in the food-seeking behaviours of individuals who are vulnerable to weight gain.
DOI: 10.5683/sp2/mifudl
title: Data from: Exposure to predators does not lead to the evolution of larger brains in experimental populations of threespine stickleback

description: AbstractNatural selection is often invoked to explain differences in brain size among vertebrates. However, the particular agents of selection that shape brain size variation remain obscure. Recent studies suggest that predators may select for larger brains because increased cognitive and sensory abilities allow prey to better elude predators. Yet, there is little direct evidence that exposure to predators causes the evolution of larger brains in prey species. We experimentally tested this prediction by exposing families of 1000-2000 F2 hybrid benthic-limnetic threespine stickleback to predators under naturalistic conditions, along with matched controls. After two generations of selection, we found that fish from the predator addition treatment had significantly smaller brains (specifically smaller telencephalons and optic lobes) than fish from the control treatment. After an additional generation of selection, we reared experimental fish in a common environment and found that this difference in brain size was maintained in the offspring of fish from the predator addition treatment. Our results provide direct experimental evidence that (a) predators can indeed drive the evolution of brain size – but not in the fashion commonly expected and (b) that the tools of experimental evolution can be used to the study the evolution of the vertebrate brain.
DOI: 10.5683/sp2/bv5jqp
title: Data from: Extensive reduction of the nuclear pore complex in nucleomorphs

description: AbstractThe nuclear pore complex (NPC) is a large macromolecular assembly situated within the pores of the nuclear envelope. Through interactions between its subcomplexes and import proteins, the NPC mediates the transport of molecules into and out of the nucleus and facilitates dynamic chromatin regulation and gene expression. Accordingly, the NPC constitutes a highly integrated nuclear component that is ubiquitous and conserved amongst eukaryotes. Potential exceptions to this are nucleomorphs: highly reduced, relict nuclei that were derived from green and red algae following their endosymbiotic integration into two lineages, the chlorarachniophytes and the cryptophyceans. A previous investigation failed to identify NPC genes in nucleomorph genomes suggesting that these genes have either been relocated to the host nucleus or lost. Here we sought to investigate the composition of the NPC in nucleomorphs by using genomic and transcriptomic data to identify and phylogenetically classify NPC proteins in nucleomorph-containing algae. Although we found NPC proteins in all examined lineages, most of those found in chlorarachniophytes and cryptophyceans were single copy, host-related proteins that lacked signal peptides. Two exceptions were Nup98 and Rae1, which had clear nucleomorph-derived homologues. However, these proteins alone are likely insufficient to structure a canonical NPC and previous reports revealed that Nup98 and Rae1 have other nuclear functions. Ultimately, these data indicate that nucleomorphs represent eukaryotic nuclei without a canonical NPC, raising fundamental questions about their structure and function.
DOI: 10.5683/sp2/kgbapt
title: Data from: Extra-pair paternity and the variance in male fitness in song sparrows (Melospiza melodia)

description: AbstractThe variance in fitness across population members can influence major evolutionary processes. In socially monogamous but genetically polygynandrous species, extra-pair paternity (EPP) is widely hypothesized to increase the variance in male fitness compared to that arising given the socially monogamous mating system. This hypothesis has not been definitively tested because comprehensive data describing males’ apparent (social) and realized (genetic) fitness have been lacking. We used 16 years of comprehensive social and genetic paternity data for an entire free-living song sparrow (Melospiza melodia) population to quantify and compare variances in male apparent and realized fitness, and to quantify the contribution of the variances in within-pair and extra-pair reproductive success and their covariance to the variance in realized fitness. Overall, EPP increased the variance in male fitness by only 0-27% across different fitness and variance measures. This relatively small effect reflected the presence of socially unpaired males with zero apparent and low realized fitness, small covariance between within- and extra-pair reproductive success and large variance in within-pair reproductive success that was relatively unaffected by EPP. Therefore, although EPP altered individual males’ contributions to future generations, its impact on population-level parameters such as the opportunity for selection and effective population size was limited.
DOI: 10.5683/sp2/pxp2er
title: Data from: Eye and head movements are complementary in visual selection

description: AbstractIn the natural environment, visual selection is accomplished by a system of nested effectors, moving the head and body within space and the eyes within the visual field. However, it is not yet known if the principles of selection for these different effectors are the same or different. We used a novel gaze-contingent display in which an asymmetric window of visibility (a horizontal or vertical slot) was yoked to either head or eye position. Participants showed highly systematic changes in behaviour, revealing clear differences in the principles underlying selection by eye and head. Eye movements were more likely to move in the direction of visible information—horizontally when viewing with a horizontal slot, and vertically with a vertical slot. Head movements showed the opposite and complementary pattern, moving to reveal new information (e.g. vertically with a horizontal slot and vice versa). These results are consistent with a nested system in which the head favours exploration of unknown regions, while the eye exploits what can be seen with finer-scale saccades.
DOI: 10.5683/sp2/axnbyq
title: Data from: Fear and lethality in snowshoe hares: the deadly effects of non-consumptive predation risk

description: AbstractPredators play a critical, top-down role in shaping ecosystems, driving prey population and community dynamics. Traditionally, studies of predator-prey interactions have focused on direct effects of predators, namely the killing of prey. More recently, the non-consumptive effects of predation risk are being appreciated; e.g., the Ecology of Fear. Prey responses to predation risk can be morphological, behavioural, and physiological, and are assumed to come at a cost to prey fitness. However, few studies have examined the relationship between predation risk and survival in wild animals. We tested the hypothesis that predation risk itself could reduce survival in wild-caught snowshoe hares. We exposed female snowshoe hares to a simulated predator (a trained dog) during gestation only, and measured adult survival and, in surviving females, their ability to successfully wean offspring. We show for the first time in a wild mammal that the risk of predation can itself be lethal. Predation risk reduced adult female survival by 30%, and had trans-generational effects, reducing offspring survival to weaning by over 85% - even though the period of risk ended at birth. As a consequence of these effects the predator-exposed group experienced a decrease in number, while the control group substantially increased. Challenges remain in determining the importance of risk-induced mortality in natural field settings; however, our findings show that non-lethal predator encounters can influence survival of both adults and offspring. Future work is needed to test these effects in free-living animals.
DOI: 10.5683/sp2/6znjnl
title: Data from: Feather melanin and micro-structure variation in dark-eyed junco (Junco hyemalis) across an elevational gradient in the Selkirk Mountains

description: AbstractVariation in feather melanism and microstructure can arise through sexual selection and ecological functional drivers. Melanin-based plumage traits are associated with sexual dichromatism and the intensity of sexual selection in many avian species, but also have several ecological benefits such as protection against ultra-violet (UV) radiation, camouflage, and feather strength. Additionally, feather microstructure influences thermoregulation. Plumage variation across species is well documented; however, the relative role of sexual selection and ecological drivers in intra-specific and within-population variation is less established. We investigated UV reflectance, melanism, and feather microstructure in a population of Oregon dark-eyed juncos Junco hyemalis oreganus between high (1900–2200 m a.s.l.) and low (450–800 m a.s.l.) elevations in the Selkirk Mountains to evaluate potential sexual selection and ecological drivers of variation. We found no difference in UV reflectance or lightness (melanism) of head feathers between elevations, but individuals at high elevation had lighter (less melanism) and less brown (less pheomelanin) body contour feathers than at low elevations. High elevation individuals also had longer contour feathers with more pronounced plumulaceous regions. Sexual dichromatism did not vary between elevations, leading us to reject sexual selection in favour of ecological functional drivers of plumage variation in this system. To our knowledge, this is the first study to identify within-population differences in feather melanism and microstructure between different elevations.