@article{10166, abstract = {While sexual reproduction is widespread among many taxa, asexual lineages have repeatedly evolved from sexual ancestors. Despite extensive research on the evolution of sex, it is still unclear whether this switch represents a major transition requiring major molecular reorganization, and how convergent the changes involved are. In this study, we investigated the phylogenetic relationship and patterns of gene expression of sexual and asexual lineages of Eurasian Artemia brine shrimp, to assess how gene expression patterns are affected by the transition to asexuality. We find only a few genes that are consistently associated with the evolution of asexuality, suggesting that this shift may not require an extensive overhauling of the meiotic machinery. While genes with sex-biased expression have high rates of expression divergence within Eurasian Artemia, neither female- nor male-biased genes appear to show unusual evolutionary patterns after sexuality is lost, contrary to theoretical expectations.}, author = {Huylmans, Ann K and Macon, Ariana and Hontoria, Francisco and Vicoso, Beatriz}, issn = {1471-2954}, journal = {Proceedings of the Royal Society B: Biological Sciences}, keywords = {asexual reproduction, parthenogenesis, sex-biased genes, sexual conflict, automixis, crustaceans}, number = {1959}, publisher = {The Royal Society}, title = {{Transitions to asexuality and evolution of gene expression in Artemia brine shrimp}}, doi = {10.1098/rspb.2021.1720}, volume = {288}, year = {2021}, } @article{7727, abstract = {Genes of the major histocompatibility complex (MHC) have been shown to influence social signalling and mate preferences in many species, including humans. First observations suggest that MHC signalling may also affect female fertility. To test this hypothesis, we exposed 191 female horses (Equus caballus) to either an MHC-similar or an MHC-dissimilar stimulus male around the time of ovulation and conception. A within-subject experimental design controlled for non-MHC-linked male characteristics, and instrumental insemination with semen of other males (n = 106) controlled for potential confounding effects of semen or embryo characteristics. We found that females were more likely to become pregnant if exposed to an MHC-dissimilar than to an MHC-similar male, while overall genetic distance to the stimulus males (based on microsatellite markers on 20 chromosomes) had no effect. Our results demonstrate that early pregnancy failures can be due to maternal life-history decisions (cryptic female choice) influenced by MHC-linked social signalling.}, author = {Burger, D. and Thomas, S. and Aepli, H. and Dreyer, M. and Fabre, G. and Marti, E. and Sieme, H. and Robinson, Matthew Richard and Wedekind, C.}, issn = {0962-8452}, journal = {Proceedings of the Royal Society B: Biological Sciences}, number = {1868}, publisher = {The Royal Society}, title = {{Major histocompatibility complex-linked social signalling affects female fertility}}, doi = {10.1098/rspb.2017.1824}, volume = {284}, year = {2017}, } @article{1993, abstract = {The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. }, author = {Konrad, Matthias and Grasse, Anna V and Tragust, Simon and Cremer, Sylvia}, issn = {1471-2954}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1799}, publisher = {The Royal Society}, title = {{Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host}}, doi = {10.1098/rspb.2014.1976}, volume = {282}, year = {2015}, } @article{7741, abstract = {Phenotypes expressed in a social context are not only a function of the individual, but can also be shaped by the phenotypes of social partners. These social effects may play a major role in the evolution of cooperative breeding if social partners differ in the quality of care they provide and if individual carers adjust their effort in relation to that of other carers. When applying social effects models to wild study systems, it is also important to explore sources of individual plasticity that could masquerade as social effects. We studied offspring provisioning rates of parents and helpers in a wild population of long-tailed tits Aegithalos caudatus using a quantitative genetic framework to identify these social effects and partition them into genetic, permanent environment and current environment components. Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects. However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect. While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.}, author = {Adams, Mark James and Robinson, Matthew Richard and Mannarelli, Maria-Elena and Hatchwell, Ben J.}, issn = {0962-8452}, journal = {Proceedings of the Royal Society B: Biological Sciences}, number = {1810}, publisher = {The Royal Society}, title = {{Social genetic and social environment effects on parental and helper care in a cooperatively breeding bird}}, doi = {10.1098/rspb.2015.0689}, volume = {282}, year = {2015}, } @article{3919, abstract = {Hamilton's concept of local mate competition (LMC) is the standard model to explain female-biased sex ratios in solitary Hymenoptera. In social Hymenoptera, however, LMC has remained controversial, mainly because manipulation of sex allocation by workers in response to relatedness asymmetries is an additional powerful mechanism of female bias. Furthermore, the predominant mating systems in the social insects are thought to make LMC unlikely. Nevertheless, several species exist in which dispersal of males is limited and mating occurs in the nest. Some of these species, such as the ant Cardiocondyla obscurior, have evolved dimorphic males, with one morph being specialized for dispersal and the other for fighting with nest-mate males over access to females. Such life history, combining sociality and alternative reproductive tactics in males, provides a unique opportunity to test the power of LMC as a selective force leading to female-biased sex ratios in social Hymenoptera. We show that, in concordance with LMC predictions, an experimental increase in queen number leads to a shift in sex allocation in favour of non-dispersing males, but does not influence the proportion of disperser males. Furthermore, we can assign this change in sex allocation at the colony level to the queens and rule out worker manipulation.}, author = {Cremer, Sylvia and Heinze, Jürgen}, issn = {0962-8452}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1489}, pages = {417 -- 422}, publisher = {Royal Society, The}, title = {{Adaptive production of fighter males: queens of the ant Cardiocondyla adjust the sex ratio under local mate competition}}, doi = {10.1098/rspb.2001.1892}, volume = {269}, year = {2002}, } @article{4288, abstract = {We measured the heterozygous effects on net fitness of a sample of 12 wild-type third chromosomes in D. melanogaster. Effects on fitness were assessed by competing the wild-type chromosomes against balancer chromosomes, to prevent the production of recombinants. The measurements were carried out in the population cage environment in which the life history had been evolving, in an undisturbed population with overlapping generations, and replicated measurements were made on each chromosome to control for confounding effects such as mutation accumulation. We found significant variation among the wild type chromosomes in their additive genetic effect on net fitness. The system provides an opportunity to obtain an accurate estimate of the distribution of heterozygous effects on net fitness, the contribution of different fitness components including male mating success, and the role of intra-chromosomal epistasis in fitness variation.}, author = {Fowler, Kevin and Semple, Colin and Barton, Nicholas H and Partridge, Linda}, issn = {0962-8452}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1379}, pages = {191 -- 199}, publisher = {The Royal Society}, title = {{Genetic variation for total fitness in Drosophila melanogaster}}, doi = {10.1098/rspb.1997.0027}, volume = {264}, year = {1997}, } @article{3637, abstract = {Hybridizing taxa remain distinct for two main reasons. Natural selection acts against hybrids either because of their incompatible genome, or because of differential adaptation of the pure types across an environmental gradient. Here, we provide experimental evidence that the location of the Bombina (Anura: Discoglossidae) hybrid zone in Croatia is, at least in part, determined by differential adaptation. B. bombina typically breeds in permanent water in the lowland, whereas B. variegata reproduces in puddles at higher elevations. In a reciprocal translocation, pure bombina and variegata tadpoles were introduced in equal proportions into lowland pond enclosures and upland puddles. After three weeks, variegata exceeded bombina in survival and growth in both habitats. The effect was most pronounced in puddles, where the few surviving bombina tadpoles had hardly grown at all. In comparison to variegata, the smaller hatchlings of bombina grew relatively faster in ponds, but remained smaller in absolute terms. Nevertheless, B. bombina appears better adapted to ponds than to puddles. The mechanisms by which variegata is excluded from ponds remain to be demonstrated. These data show that habitat dependent selection prevents the invasion of bombina tadpole traits into the variegata gene pool. Given the strong linkage disequilibria in hybrid populations, differential selection on tadpoles may be sufficient to maintain the integrity of the two gene pools.}, author = {Maccallum, Catriona and Nürnberger, Beate and Barton, Nicholas H}, issn = {0962-8452}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1359}, pages = {257 -- 264}, publisher = {Royal Society of London}, title = {{Experimental evidence for habitat dependent selection in a Bombina hybrid zone}}, doi = {10.1098/rspb.1995.0089}, volume = {260}, year = {1995}, }