Search results for "sexual conflict"

Long-term fitness consequences of high yolk androgen levels: sons pay the costs

2012

Summary 1. Early growth conditions, for example hormonal environment during embryonic development, may have long-lasting effects on behaviour and phenotype, with subsequent fitness consequences. Yolk androgens have been shown to affect various offspring traits in the short-term, but fitness consequences for either offspring or parents, a prerequisite for studying the adaptiveness of this maternal effect, are poorly known in the wild. 2. We experimentally elevated yolk androgen levels of whole clutches in a wild population of collared flycatchers (Ficedula albicollis) and investigated the long-term effects of yolk androgens on offspring local recruitment, parental return rate, and timing and…

Socio-Reproductive Conflicts and the Father’s Curse Dilemma

2018

Evolutionary conflicts between males and females can manifest over sexually antagonistic interactions at loci or over sexually antagonistic interests within a locus. The latter form of conflict, intralocus sexual conflict, arises from sexually antagonistic selection and constrains the fitness of individuals through a phenotypic compromise. These conflicts, and socio-reproductive interactions in general, are commonly mediated by hormones, and thus predictive insights can be gained from studying their mediating effects. Here, we integrate several lines of evidence to describe a novel, hormonally mediated reproductive dilemma that we call the father’s curse, which results from an intralocus co…

2016

AbstractGenetic manipulations in nutrient-sensing pathways are known to both extend lifespan and modify responses to environmental stressors (e.g., starvation, oxidative and thermal stresses), suggesting that similar mechanisms regulate lifespan and stress resistance. However, despite being a key factor reducing female lifespan and affecting female fitness, male-induced harm has rarely been considered as a stressor mediated by nutrient sensing pathways. We explored whether a lifespan-extending manipulation also modifies female resistance to male-induced harm. To do so, we used long-lived female Drosophila melanogaster that had their insulin signalling pathway downregulated by genetically ab…

2018

Sex differences in lifespan are ubiquitous, but the underlying causal factors remain poorly understood. Inter- and intrasexual social interactions are well known to influence lifespan in many taxa, but it has proved challenging to separate the role of sex-specific behaviours from wider physiological differences between the sexes. To address this problem, we genetically manipulated the sexual identity of the nervous system—and hence sexual behaviour—in Drosophila melanogaster , and measured lifespan under varying social conditions. Consistent with previous studies, masculinization of the nervous system in females induced male-specific courtship behaviour and aggression, while nervous system…

Interactions between the sexual identity of the nervous system and the social environment mediate lifespan in Drosophila melanogaster

2018

Sex differences in lifespan are ubiquitous, but the underlying causal factors remain poorly understood. Inter- and intrasexual social interactions are well known to influence lifespan in many taxa, but it has proved challenging to separate the role of sex-specific behaviours from wider physiological differences between the sexes. To address this problem, we genetically manipulated the sexual identity of the nervous system—and hence sexual behaviour—in Drosophila melanogaster, and measured lifespan under varying social conditions. Consistent with previous studies, masculinization of the nervous system in females induced male-specific courtship behaviour and aggression, while nervous system f…

2015

Competition over access to reproductive opportunities can lead males to harm females. However, recent work has shown that, in Drosophila melanogaster, male competition and male harm of females are both reduced under conditions simulating male-specific population viscosity (i.e., in groups where males are related and reared with each other as larvae). Here, we seek to replicate these findings and investigate whether male population viscosity can have repercussions for the fitness of offspring in the next generation. We show that groups of unrelated-unfamiliar (i.e., unrelated individuals raised apart) males fight more intensely than groups of related-familiar males (i.e., full siblings raise…

Genomic conflicts and sexual antagonism in human health: Insights from oxytocin and testosterone

2015

We review the hypothesized and observed effects of two of the major forms of genomic conflicts, genomic imprinting and sexual antagonism, on human health. We focus on phenotypes mediated by peptide and steroid hormones (especially oxytocin and testosterone) because such hormones centrally mediate patterns of physical and behavioral resource allocation that underlie both forms of conflict. In early development, a suite of imprinted genes modulates the human oxytocinergic system as predicted from theory, with paternally inherited gene expression associated with higher oxytocin production, and increased solicitation to mothers by infants. This system is predicted to impact health through the i…

Does foreplay matter? Gammarus pulex females may benefit from long-lasting precopulatory mate guarding.

2011

Precopulatory mate guarding (PCMG) is generally assumed to be costly for both sexes. However, males may gain by displaying long-lasting mate guarding under strong male–male competition. Surprisingly, the potential for females to benefit from being held by males has been largely overlooked in previous studies. In Gammarus pulex , an amphipod crustacean, PCMG lasts several weeks, yet females are described as bearing only cost from such male mating strategy. We investigated potential female benefits by assessing the effect of mate guarding on her intermoult duration. Unpaired females had longer intermoult duration than paired females. Intermoult duration clearly decreased when paired females …

Sexual and postmating reproductive isolation between allopatric Drosophila montana populations suggest speciation potential

2011

This work was funded by a European Commission Research Training Grant RTN2-2001-00049, the Centre of Excellence for Evolutionary Research at the University of Jyväskylä and a Marie Curie Initial Training Network, ‘Understanding the evolutionary origin of biological diversity’ (ITN-2008-213780 SPECIATION) Background: Widely distributed species with populations adapted to different environmental conditions can provide valuable opportunities for tracing the onset of reproductive incompatibilities and their role in the speciation process. Drosophila montana, a D. virilis group species found in high latitude boreal forests in Nearctic and Palearctic regions around the globe, could be an excellen…

Intralocus sexual conflict for fitness: sexually antagonistic alleles for testosterone

2011

Intralocus sexual conflict occurs when a trait encoded by the same genetic locus in the two sexes has different optima in males and females. Such conflict is widespread across taxa, however, the shared phenotypic traits that mediate the conflict are largely unknown. We examined whether the sex hormone, testosterone (T), that controls sexual differentiation, contributes to sexually antagonistic fitness variation in the bank vole, Myodes glareolus . We compared (opposite-sex) sibling reproductive fitness in the bank vole after creating divergent selection lines for T. This study shows that selection for T was differentially associated with son versus daughter reproductive success, causing a …