The role of indirect genetic effects in the evolution of interacting reproductive behaviors in the burying beetle, Nicrophorus vespilloides (original) (raw)
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Behavioral plasticity and GxE of reproductive tactics in Nicrophorus vespilloides burying beetles
Evolution, 2015
Phenotypic plasticity is important in the evolution of traits and facilitates adaptation to rapid environmental changes. However, variation in plasticity at the individual level, and the heritable basis underlying this plasticity is rarely quantified for behavioral traits. Alternative behavioral reproductive tactics are key components of mating systems but are not often considered within a phenotypic plasticity framework (i.e., as reaction norms). Here, using lines artificially selected for repeated mating rate, we test for genetic (G × E) sources of variation in reproductive behavior of male Nicrophorus vespilloides burying beetles (including signaling behavior), as well as the role of individual body size, in responsiveness to changes in social environment. The results show that body size influences the response of individuals' signaling behavior to changes in the social environment. Moreover, there was G × E underlying the responses of males to variation in the quality of social environment experienced (relative size of focal male compared to his rival). This shows that individual variation in plasticity and social sensitivity of signaling behavior can evolve in response to selection on investment in mating behavior, with males selected for high mating investment having greater social sensitivity.
Selection, Inheritance, and the Evolution of Parent‐Offspring Interactions
The American Naturalist, 2004
Very few studies have examined parent-offspring interactions from a quantitative genetic perspective. We used a crossfostering design and measured genetic correlations and components of social selection arising from two parental and two offspring behaviors in the burying beetle Nicrophorus vespilloides. Genetic correlations were assessed by examining behavior of relatives independent of common social influences. We found positive genetic correlations between all pairs of behaviors, including between parent and offspring behaviors. Patterns of selection were assessed by standardized performance and selection gradients. Parental provisioning had positive effects on offspring performance and fitness, while remaining near the larvae without feeding them had negative effects. Begging had positive effects on offspring performance and fitness, while increased competition among siblings had negative effects. Coadaptations between parenting and offspring behavior appear to be maintained by genetic correlations and functional trade-offs; parents that feed their offspring more also spend more time in the area where they can forage for themselves. Families with high levels of begging have high levels of sibling competition. Integrating information from genetics and selection thus provides a general explanation for why variation persists in seemingly beneficial traits expressed in parent-offspring interactions and illustrates why it is important to measure functionally related suites of behaviors.
Adaptation and the genetics of social behaviour
2009
In recent years much progress has been made towards understanding the selective forces involved in the evolution of social behaviour including conflicts over reproduction among group members. Here, I argue that an important additional step necessary for advancing our understanding of the resolution of potential conflicts within insect societies is to consider the genetics of the behaviours involved. First, I discuss how epigenetic modifications of behaviour may affect conflict resolution within groups. Second, I review known natural polymorphisms of social organization to demonstrate that a lack of consideration of the genetic mechanisms involved may lead to erroneous explanations of the adaptive significance of behaviour. Third, I suggest that, on the basis of recent genetic studies of sexual conflict in Drosophila, it is necessary to reconsider the possibility of within-group manipulation by means of chemical substances (i.e. pheromones). Fourth, I address the issue of direct versus indirect genetic effects, which is of particular importance for the study of behaviour in social groups. Fifth, I discuss the issue of how a genetic influence on dominance hierarchies and reproductive division of labour can have secondary effects, for example in the evolution of promiscuity. Finally, because the same sets of genes (e.g. those implicated in chemical signalling and the responses that are triggered) may be used even in species as divergent as ants, cooperative breeding birds and primates, an integration of genetic mechanisms into the field of social evolution may also provide unifying ideas.
The evolution of repeated mating in the burying beetle, Nicrophorus vespilloides
2008
Animals of many species accept or solicit recurring copulations with the same partner; i.e., show repeated mating. An evolutionary explanation for this excess requires that the advantages of repeated mating outweigh the costs, and that behavioral components of repeated mating are genetically influenced. There can be benefits of repeated mating for males when there is competition for fertilizations or where the opportunities for inseminating additional mates are rare or unpredictable. The benefits to females are less obvious and, depending on underlying genetic architecture, repeated mating may have evolved as a correlated response to selection on males. We investigated the evolution of repeated mating with the same partner in the burying beetle Nicrophorus vespilloides by estimating the direct and indirect fitness benefits for females and the genetics of behavior underlying repeated mating. The number of times a female mated had minimal direct and no indirect fitness benefits for females. The behavioral components of repeated mating (mating frequency and mating speed) were moderately negatively genetically correlated in males and uncorrelated in females. However, mating frequency and mating speed were strongly positively genetically correlated between males and females. Our data suggest that repeated mating by female N. vespilloides may have evolved as a correlated response to selection on male behavior rather than in response to benefits of repeated mating for females.
Genetics and Evolution of Social Behavior in Insects
Annual Review of Genetics, 2016
The study of insect social behavior has offered tremendous insight into the molecular mechanisms mediating behavioral and phenotypic plasticity. Genomic applications to the study of eusocial insect species, in particular, have led to several hypotheses for the processes underlying the molecular evolution of behavior. Advances in understanding the genetic control of social organization have also been made, suggesting an important role for supergenes in the evolution of divergent behavioral phenotypes. Intensive study of social phenotypes across species has revealed that behavior and caste are controlled by an interaction between genetic and environmentally mediated effects and, further, that gene expression and regulation mediate plastic responses to environmental signals. However, several key methodological flaws that are hindering progress in the study of insect social behavior remain. After reviewing the current state of knowledge, we outline ongoing challenges in experimental des...
Evolution, 2016
Male and female genital morphology varies widely across many taxa, and even among populations. Disentangling potential sources of selection on genital morphology is problematic because each sex is predicted to respond to adaptations in the other due to reproductive conflicts of interest. To test how variation in this sexual conflict trait relates to variation in genital morphology we used our previously developed artificial selection lines for high and low repeated mating rates. We selected for high and low repeated mating rates using monogamous pairings to eliminate contemporaneous female choice and male-male competition. Male and female genital shape responded rapidly to selection on repeated mating rate. High and low mating rate lines diverged from control lines after only 10 generations of selection. We also detected significant patterns of male and female genital shape coevolution among selection regimes. We argue that because our selection lines differ in sexual conflict, these results support the hypothesis that sexually antagonistic coevolution can drive the rapid divergence of genital morphology. The greatest divergence in morphology corresponded with lines in which the resolution of sexual conflict over mating rate was biased in favor of male interests.
1 The Nicrophorus vespilloides genome and methylome , a beetle with complex social behavior 1 2
2015
20. CC-BY 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not. Abstract 22 Testing for conserved and novel mechanisms underlying phenotypic evolution requires a diversity of 23 genomes available for comparison spanning multiple independent lineages. For example, complex social 24 behavior in insects has been investigated primarily with eusocial lineages, nearly all of which are 25 Hymenoptera. If conserved genomic influences on sociality do exist, we need data from a wider range of taxa 26 that also vary in their levels of sociality. Here we present information on the genome of the subsocial beetle 27 Nicrophorus vespilloides, a species long used to investigate evolutionary questions of complex social 28 behavior. We used this genome to address two questions. First, does life history predict overlap in gene 29 models more strongly than phylogenetic groupings? Second, like other insects with...
Behavioral Ecology, 2006
Alternative reproductive tactics can be maintained through different evolutionary avenues. They can be genetically or stochastically determined, in which case they must yield equal fitness, or their use can be conditional, in which case the fitness payoff of alternatives may differ. We attempted to assess the reproductive success of alternative reproductive tactics employed by wild male and female burying beetles in natural associations on carcasses placed in the field. A beetle's reproductive tactic was defined by its potential involvement in care of larvae, and parentage was assessed using oligolocus DNA fingerprinting of offspring and potential parents. Both in males and in females, alternative tactics yielded significantly different reproductive benefits: subordinate females (brood parasites) and males (satellite males) had considerably lower reproductive success than dominant or uncontested individuals. Joint breeding was too infrequent for statistical inferences, generating intermediate offspring numbers. About 15% of offspring were sired by males not present on the carcass, suggesting that mating away from reproductive resources can produce reproductive benefits to males. Our results, in concert with the observation that beetles using one tactic can be manipulated into employing the alternative, support the notion that Nicrophorus vespilloides uses alternatives conditionally, opportunistically employing lower-benefit tactics when more profitable tactics are not available, or as additional ''on-the-side'' tactics to bolster reproductive success.