scholarly journals The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus

2010 ◽  
Vol 24 (2) ◽  
pp. 449-456 ◽  
Author(s):  
L. GAY ◽  
E. BROWN ◽  
T. TREGENZA ◽  
D. PINCHEIRA-DONOSO ◽  
P. E. EADY ◽  
...  
Keyword(s):  
Sexual Conflict ◽  
Genetic Architecture ◽  
Callosobruchus Maculatus ◽  
Female Resistance

scholarly journals Sexual conflict and correlated evolution between male persistence and female resistance traits in the seed beetle Callosobruchus maculatus

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170132 ◽  
Author(s):  
Liam R. Dougherty ◽  
Emile van Lieshout ◽  
Kathryn B. McNamara ◽  
Joe A. Moschilla ◽  
Göran Arnqvist ◽  
...  
Keyword(s):  
Sexual Conflict ◽  
Male Genitalia ◽  
Callosobruchus Maculatus ◽  
Negative Relationship ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
Correlated Evolution ◽  
Male And Female ◽  
Seed Beetle ◽  
Trade Offs

Traumatic mating (or copulatory wounding) is an extreme form of sexual conflict whereby male genitalia physically harm females during mating. In such species females are expected to evolve counter-adaptations to reduce male-induced harm. Importantly, female counter-adaptations may include both genital and non-genital traits. In this study, we examine evolutionary associations between harmful male genital morphology and female reproductive tract morphology and immune function across 13 populations of the seed beetle Callosobruchus maculatus . We detected positive correlated evolution between the injuriousness of male genitalia and putative female resistance adaptations across populations. Moreover, we found evidence for a negative relationship between female immunity and population productivity, which suggests that investment in female resistance may be costly due to the resource trade-offs that are predicted between immunity and reproduction. Finally, the degree of female tract scarring (harm to females) was greater in those populations with both longer aedeagal spines and a thinner female tract lining. Our results are thus consistent with a sexual arms race, which is only apparent when both male and female traits are taken into account. Importantly, our study provides rare evidence for sexually antagonistic coevolution of male and female traits at the within-species level.

Males evolve to be more harmful under increased sexual conflict intensity in a seed beetle

2020 ◽  
Vol 31 (2) ◽  
pp. 591-597 ◽  
Author(s):  
Kathryn B McNamara ◽  
Nadia S Sloan ◽  
Sian E Kershaw ◽  
Emile van Lieshout ◽  
Leigh W Simmons
Keyword(s):  
Sexual Conflict ◽  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
Seed Beetle ◽  
Copulation Behavior ◽  
Tract Damage ◽  
Full Factorial ◽  
Conflict Intensity

Abstract One conspicuous manifestation of sexual conflict is traumatic mating, in which male genitalia damage the female during copulation. The penis of the seed beetle, Callosobruchus maculatus, is covered in spines that damage the female reproductive tract. Females kick males ostensibly to shorten these harmful copulations. How these iconic conflict behaviors coevolve in response to sexual conflict intensity can provide insight into the economics of these traits. We examined whether male harm and female resistance coevolved in response to elevated sexual conflict. We quantified copulation behavior and female reproductive tract damage of individuals from replicated populations evolving for 32 generations under low or high sexual conflict (female- and male-biased treatments, respectively). First, we permitted females ad libitum matings with males from either sex-ratio treatment, recording her tract damage and longevity. Second, we performed a full-factorial cross of matings by males and females from each of the replicate populations, recording mating and kicking duration and reproductive output. We found manipulation of sexual conflict intensity led to the evolution of male harmfulness, but not female resistance to harm. We also demonstrate that female kicking does not respond to sexual conflict intensity, suggesting it does not function to mitigate male harm in this species. Our findings demonstrate the complexities of behavioral and morphological coevolutionary responses to sexual conflict intensity in an important model species.

scholarly journals Quantifying variation in female internal genitalia: no evidence for plasticity in response to sexual conflict risk in a seed beetle

2021 ◽  
Vol 288 (1954) ◽  
pp. 20210746
Author(s):  
Blake W. Wyber ◽  
Liam R. Dougherty ◽  
Kathryn McNamara ◽  
Andrew Mehnert ◽  
Jeremy Shaw ◽  
...  
Keyword(s):  
Social Environment ◽  
Sexual Conflict ◽  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Dimensional Space ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
The Social ◽  
Low Levels ◽  
Seed Beetles

Sexually antagonistic coevolution can drive the evolution of male traits that harm females, and female resistance to those traits. While males have been found to vary their harmfulness to females in response to social cues, plasticity in female resistance traits remains to be examined. Here, we ask whether female seed beetles Callosobruchus maculatus are capable of adjusting their resistance to male harm in response to the social environment. Among seed beetles, male genital spines harm females during copulation and females might resist male harm via thickening of the reproductive tract walls. We develop a novel micro computed tomography imaging technique to quantify female reproductive tract thickness in three-dimensional space, and compared the reproductive tracts of females from populations that had evolved under high and low levels of sexual conflict, and for females reared under a social environment that predicted either high or low levels of sexual conflict. We find little evidence to suggest that females can adjust the thickness of their reproductive tracts in response to the social environment. Neither did evolutionary history affect reproductive tract thickness. Nevertheless, our novel methodology was capable of quantifying fine-scale differences in the internal reproductive tracts of individual females, and will allow future investigations into the internal organs of insects and other animals.

scholarly journals Male harassment leads to fitness costs for females by disrupting oviposition site preferences

2020 ◽  
Vol 31 (3) ◽  
pp. 611-617
Author(s):  
Elisabeth Bacon ◽  
Flavia Barbosa
Keyword(s):  
Clutch Size ◽  
Sexual Conflict ◽  
Egg Size ◽  
Callosobruchus Maculatus ◽  
Optimal Number ◽  
Oviposition Site ◽  
Fitness Costs ◽  
Male Harassment ◽  
Oviposition Substrate ◽  
Pinto Beans

Abstract In many species, a difference in the optimal number of copulations for males and females leads to sexual conflict. This is well documented in the bean beetle Callosobruchus maculatus, where both sexes mate multiply and females incur fitness costs from injuries caused by the male genitalia. Here, we demonstrate that sexual conflict also decreases female fitness due to male harassment. We hypothesized that harassment costs would come as 1) decreased clutch size, egg size, or both and by 2) disruption of female preference for higher-quality oviposition substrate. Mated females were housed with two bean types—cowpeas, their preferred natal hosts, and toxic pinto beans. They were then submitted to either no, moderate, or high male harassment in the oviposition site. Females under harassment produced smaller clutch sizes but not smaller eggs, resulting in the absence of an egg-size/clutch-size trade-off. Additionally, females did not exhibit a preference for their natal cowpeas hosts over toxic pinto beans when males were present at the oviposition site, although they do so when harassing males are not present. Harassment disrupted female responses to variation in oviposition substrate quality, resulting in considerable fitness consequences in the form of lower offspring production and survival.

scholarly journals Kin but less than kind: within-group male relatedness does not increase female fitness in seed beetles

2019 ◽  
Vol 286 (1910) ◽  
pp. 20191664 ◽  
Author(s):  
Elena C. Berg ◽  
Martin I. Lind ◽  
Shannon Monahan ◽  
Sophie Bricout ◽  
Alexei A. Maklakov
Keyword(s):  
Sexual Conflict ◽  
Callosobruchus Maculatus ◽  
Lifetime Reproductive Success ◽  
Cognitive Error ◽  
Individual Fitness ◽  
Adaptive Mechanisms ◽  
Female Survival ◽  
Reproductive Part ◽  
Seed Beetles

Theory maintains within-group male relatedness can mediate sexual conflict by reducing male–male competition and collateral harm to females. We tested whether male relatedness can lessen female harm in the seed beetle Callosobruchus maculatus . Male relatedness did not influence female lifetime reproductive success or individual fitness across two different ecologically relevant scenarios of mating competition. However, male relatedness marginally improved female survival. Because male relatedness improved female survival in late life when C. maculatus females are no longer producing offspring, our results do not provide support for the role of within-group male relatedness in mediating sexual conflict. The fact that male relatedness improves the post-reproductive part of the female life cycle strongly suggests that the effect is non-adaptive. We discuss adaptive and non-adaptive mechanisms that could result in reduced female harm in this and previous studies, and suggest that cognitive error is a likely explanation.

scholarly journals Male-biased gene expression resolves sexual conflict through the evolution of sex-specific genetic architecture

2018 ◽  
Vol 2 (2) ◽  
pp. 52-61 ◽  
Author(s):  
Alison E. Wright ◽  
Matteo Fumagalli ◽  
Christopher R. Cooney ◽  
Natasha I. Bloch ◽  
Filipe G. Vieira ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sexual Conflict ◽  
Genetic Architecture ◽  
Evolution Of Sex

scholarly journals Offspring viability benefits but no apparent costs of mating with high quality males

2010 ◽  
Vol 7 (3) ◽  
pp. 419-421 ◽  
Author(s):  
Leigh W. Simmons ◽  
Rebecca Holley
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Alternative Hypothesis ◽  
Dung Beetle ◽  
Male Courtship ◽  
High Quality ◽  
Female Resistance ◽  
Genetic Quality ◽  
Onthophagus Taurus ◽  
Courtship Signals

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus , females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg–adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.

scholarly journals No support for the sexy-sperm hypothesis in the seed beetle: sons of monandrous females fare better in post-copulatory competition

2018 ◽  
Author(s):  
Kristin A. Hook
Keyword(s):  
Sperm Competition ◽  
Genetic Architecture ◽  
Callosobruchus Maculatus ◽  
Empirical Work ◽  
Male Mating ◽  
Genetic Constraints ◽  
Seed Beetle ◽  
Indirect Fitness ◽  
Post Hoc ◽  
Sexy Sperm

ABSTRACTThe sexy-sperm hypothesis posits that polyandrous females derive an indirect fitness benefit from multi-male mating because they increase the probability their eggs are fertilized by males whose sperm have high fertilizing efficiency, which is assumed to be heritable and conferred on their sons. However, whether this process occurs is contentious because father-to-son heritability may be constrained by the genetic architecture underlying traits important in sperm competition within certain species. Previous empirical work has revealed such genetic constraints in the seed beetle,Callosobruchus maculatus, a model system in sperm competition studies in which female multi-male mating is ubiquitous. Using the seed beetle, I tested a critical prediction of the sexy-sperm hypothesis that polyandrous females produce sons that are on average more successful under sperm competition than sons from monandrous females. Contrary to the prediction of the sexy-sperm hypothesis, I found that sons from monandrous females had significantly higher relative paternity in competitive double matings. Moreover, post-hoc analyses revealed that these sons produced significantly larger ejaculates when second to mate, despite being smaller. This study is the first to provide empirical evidence for post-copulatory processes favoring monandrous sons and discusses potential explanations for the unexpected bias in paternity.

scholarly journals Endless forms of sexual selection

2019 ◽  
Author(s):  
Willow R Lindsay ◽  
Staffan Andersson ◽  
Badreddine Bererhi ◽  
Jacob Höglund ◽  
Arild Johnsen ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Mate Choice ◽  
Sexual Conflict ◽  
Genetic Architecture ◽  
Mating Systems ◽  
Population Divergence ◽  
Trait Evolution ◽  
Mating Competition ◽  
Mhc Genes

The field of sexual selection has burgeoned with research into trait evolution in the context of ecology, sociality, phylogeny, natural selection, and sexual conflict. This paper is the product of a “stock-taking” workshop; our aim is to stimulate discussion, not to provide an exhaustive review. We identify outstanding questions organized into four thematic sections. 1) Evolution of mate choice and mating systems. Variation in mate quality can generate mating competition and choice in either sex with implications for the evolution of mating systems. Limitations on mate choice may dictate the importance of direct vs. indirect benefits in mating decisions and consequently, mating systems. Specifically, polyandry evolves in response to the strength of pre- vs. post-copulatory selection. The evolution of polyandry may be related to diversity of pathogens and Major Histocompatibility Complex (MHC) genes. MHC genes are also potential cues of kinship in avoidance of inbreeding. The balance between inbreeding avoidance and inclusive fitness in mating decisions deserves greater attention. 2) Sender and receiver mechanisms shaping signal design. Mediation of honest signal content likely depends on integration of temporally variable social and physiological costs that are a challenge to measure. The neuroethology of sensory and cognitive receiver biases is the main key to signal form and the ‘aesthetic sense’ proposed by Darwin. Since a receiver bias is sufficient to both start and drive ornament or armament exaggeration, without a genetically correlated or even coevolving receiver, this may be the appropriate ‘null model’ of sexual selection. 3) Genetic architecture of sexual selection. Despite advances in modern molecular techniques, the number and identity of genes underlying performance remain largely unknown. A combination of genomic techniques and long-term field studies that reveal ecological correlates of reproductive success is warranted. In-depth investigations into the genetic basis of sexual dimorphism will reveal constraints and trajectories of sexually selected trait evolution. 4) Sexual selection and conflict as drivers of speciation. Population divergence and speciation is often driven by an interplay between sexual and natural selection. To what extent sexual selection promotes or counteracts population divergence may differ depending on the genetic architecture of traits as well as covariance between mating competition and local adaptation, if traits have multiple functions and if sensory systems used in mate choice are locally adapted. Also, post-copulatory processes, e.g. selection against heterospecific sperm, may influence the importance of sexual selection. Sexual conflict can shape speciation processes, since mate choice selection on females can restrict gene flow whereas selection on males is permissive. We propose that efforts to resolve these four themes can catalyze conceptual progress in the field of sexual selection.

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