Biology subjects

Burke, N. W.

Publications and source records attributed to Burke, N. W..

5 recordsLinked to original sources

bioRxiv2025

Extra-genital wounding delays remating in the sexually cannibalistic springbok mantis

A fascinating consequence of sexual conflict in animals is the maintenance of traits in males that cause physical damage to females during mating interactions. Such harm is hypothesised to be either an adaptation that enhances male fitness, or a collateral side-effect of adaptations that benefit males in other contexts. Tests of these hypotheses have mostly focused on traumatic copulation, where males wound females internally with weaponised genitalia, despite the widespread occurrence of extra-genital injury inflicted by non-genitalic structures like teeth, fangs or claws. Here, we take advantage of the unique mating interactions of the sexually cannibalistic springbok mantis, Miomantis caffra, to investigate the evolution of extra-genital wounding. Males of this species use their foretibial claws to stab females in the abdomen while fighting back against cannibalistic attacks during mating attempts. If stabbing females is adaptive, we predicted that experimentally wounded females would alter their remating behaviour or reproductive scheduling to the benefit of their mates. We found that injured females did not differ in their attractiveness or remating likelihood compared to intact females, and did not show an enhanced propensity to attack second courting males. Injured females also showed no change in mortality, fecundity, or offspring production that would suggest terminal investment due to male manipulation through wounding. However, our experiments revealed a statistically significant delay in the timing of remating among injured females, which could be interpreted as a benefit to males if such a delay reduces sperm competition. But given that remating was not prevented, only deferred, the injury-induced delay we observed is unlikely to be ecologically important, although field studies would be required to confirm this. Taken together, our results suggest that extra-genital wounding in the springbok mantis is unlikely to be adaptive but may instead be a pleiotropic side-effect of males trying to avoid being cannibalised.

evolutionary biology↗

bioRxiv2022

Genetic and phenotypic consequences of local transitions between sexual and parthenogenetic reproduction in the wild

Transitions from sexual to asexual reproduction have occurred in numerous lineages across the tree of life, but it remains unclear why asexual populations rarely persist. In facultatively parthenogenetic animals, all-female populations can arise when males are absent or become extinct, and such populations can give rise to obligately asexual species. Facultative parthenogens could therefore shed light on the initial stages of transitions to asexuality, and the factors that determine the success or failure of asexual populations. Here, we describe a novel spatial mosaic of mixed-sex and all-female populations of the facultatively parthenogenetic Australian phasmid Megacrania batesii, and use this system to investigate the consequences of reproductive mode variation in the wild. Analysis of single nucleotide polymorphisms (SNPs) indicated multiple, independent transitions between reproductive modes. As expected, all-female populations had drastically reduced heterozygosity and genetic diversity relative to mixed-sex populations. However, we found few consistent differences in fitness-related traits between population types. All-female populations exhibited more frequent and severe (non-functional) wing deformities, but did not show higher rates of appendage loss. All-female populations also harbored more parasites, but only in certain habitats. Reproductive mode explained little variation in female body size, fecundity, or egg hatch-rate. Our results confirm that transitions to parthenogenetic reproduction can lead to dramatic reductions in genetic diversity and heterozygosity. However, our findings also suggest that asexual M. batesii populations consist of high-fitness genotypes that might be able to thrive for many generations, perhaps until they encounter a drastic environmental change to which they are unable to adapt.

evolutionary biology↗

bioRxiv2021

Increased male mating success in the presence of prey and rivals in a sexually cannibalistic mantis

Pre-copulatory sexual cannibalism--or cannibalism without mating--is expected to promote the evolution of male strategies that enhance mating success and reduce the risk of cannibalism, such as preferential mating with feeding females. However, sexual selection on male competitiveness may alter male courtship decisions in the face of cannibalism risk. We investigated the effect of prey availability and rival presence on male mating decisions in the highly cannibalistic Springbok mantis, Miomantis caffra. We found that males approached females more rapidly and mated more often in the presence of prey, suggesting that females distracted with foraging may be less of a threat. The presence of a rival also hastened the onset of copulation and led to higher mating success, with very large effects occurring in the presence of both prey and rivals, indicating that intrasexual competition may intensify attraction to foraging females. Taken together, our results suggest that pre-copulatory cannibalism has selected for male preference for foraging females, and that males adjust their mating strategy to both the risk of competition and the threat of cannibalism. LAY SUMMARYDeciding when to approach a mate is critical for male mantises at risk of being cannibalised. A male might do well to pounce when a female is distracted with prey, but what if a nearby male has the same intention? In the Springbok mantis, we show that males mate faster and with greater success when both prey and a rival are present, suggesting that mating decisions depend on the dual threats of cannibalism and competition.

animal behavior and cognition↗

bioRxiv2019

Sexual conflict explains diverse patterns of transgenerational plasticity

Transgenerational plasticity (TGP) occurs when the environment experienced by parents induces changes in traits of offspring and/or subsequent generations. Such effects can be adaptive or non-adaptive and are increasingly recognised as key determinants of health, cognition, development and performance across a wide range of taxa, including humans. While the conditions that favour maternal TGP are well understood, rapidly accumulating evidence indicates that TGP can be maternal or paternal, and offspring responses can be sex-specific. However, the evolutionary mechanisms that drive this diversity are unknown. We used an individual-based model to investigate the evolution of TGP when the sexes experience different ecologies. We find that adaptive TGP rarely evolves when alleles at loci that determine offspring responses to environmental information originating from the mother and father are subject to sexually antagonistic selection. By contrast, duplication and sex-limitation of such loci can allow for the evolution of a variety of sex-specific responses, including non-adaptive sex-specific TGP when sexual selection is strong. Sexual conflict could therefore help to explain why adaptive TGP evolves in some species but not others, why sons and daughters respond to parental signals in different ways, and why complex patterns of sex-specific TGP may often be non-adaptive.

evolutionary biology↗

bioRxiv2017

Male coercion, female resistance, and the evolutionary trap of sexual reproduction

Recent theory suggests that male coercion could contribute to the maintenance of obligate sex. However, it is unclear how sexually antagonistic coevolution might interact with mate scarcity to influence the probability of invasions of obligately sexual populations by mutants capable of parthenogenetic reproduction. Furthermore, if invasion does occur, it is unclear which factors promote or prevent the complete loss of sex. Using individual-based models, we show that male coercion cannot prevent the invasion of a mutant allele that gives virgin females the ability to reproduce parthenogenetically because mutants always benefit by producing at least some offspring asexually prior to mating. Indeed, the likelihood of invasion generally increases as sexual conflict intensifies, and the effects of sexual conflict and mate scarcity can interact in complex ways to promote invasion. Nonetheless, we find that coercion prevents the complete loss of sex unless linkage disequilibrium can build up between the mutant allele and alleles for effective female resistance. Our findings clarify how costs and limitations of female resistance can promote the maintenance of sexual reproduction, turning sex into an evolutionary trap. At the same time, our results highlight the need to explain why facultative reproductive strategies so rarely evolve in nature.

evolutionary biology↗