Data from: Sexual conflict and correlated evolution between male persistence and female resistance traits in the seed beetle Callosobruchus maculatus

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.

创伤性交配（Traumatic mating，亦称交配创伤）是一种极端的性冲突（sexual conflict）形式，指雄性生殖器（male genitalia）在交配过程中对雌性造成物理伤害的现象。在这类物种中，雌性理论上会演化出反适应（counter-adaptations）策略以减轻雄性诱导的伤害。值得注意的是，雌性的反适应既可能涉及生殖器相关性状，也可能涵盖非生殖器性状。本研究以13个种群的豆象（Callosobruchus maculatus）为研究对象，探究了雄性生殖器有害形态与雌性生殖道形态（reproductive tract morphology）、免疫功能（immune function）之间的演化关联。我们在不同种群中检测到雄性生殖器的伤害性与推定的雌性抗性适应（resistance adaptations）之间存在正相关的协同演化（correlated evolution）关系。此外，我们发现雌性免疫能力与种群生产力（population productivity）之间呈负相关关系，这表明雌性抗性的投入可能存在进化代价，这一结果与免疫与繁殖间预期的资源权衡（resource trade-offs）理论相符。最后，在同时具备更长阳茎棘（aedeagal spines）且雌性生殖道衬里更薄的种群中，雌性生殖道的疤痕程度（即雌性受到的伤害）更为显著。综上，我们的研究结果符合性军备竞赛（sexual arms race）的理论预期，而这一关联仅在同时考量雌雄两性性状时才会显现。尤为重要的是，本研究为种内水平上雌雄两性性状的性拮抗协同演化（sexually-antagonistic coevolution）提供了罕见的实证证据。