Data from: Territory defense as a condition-dependent component of male reproductive success in Drosophila serrata

Sexual selection arises from both intrasexual competition and mate choice. With respect to the evolution of male traits, there is a vast literature documenting the existence of female choice and male-male competition, and both have been shown to co-occur in many species. Despite numerous studies of these two components of male reproductive success in isolation, few have investigated whether and how they interact to determine total sexual selection. To address this, we investigate male territoriality in Drosophila serrata, a species in which female preference for male sexual pheromones (cuticular hydrocarbons or CHCs) have been extensively studied. We demonstrate that territoriality occurs, that it involves direct male-male aggressive interactions, and that it contributes to variation in male mating success. Results from a phenotypic manipulation also indicate that territorial success is condition-dependent, although a genetic manipulation of condition, involving three generations of full-sib inbreeding, failed to find a significant effect. Finally, selection assays also suggest that territorial success depends on male body size but not on CHCs, whereas the opposite is true for mating success.

性选择源于同性竞争与配偶选择两大演化过程。针对雄性性状的进化，已有大量文献记录了雌性选择与雄性间竞争的普遍存在，且二者已被证实共同出现于诸多物种之中。尽管已有众多研究分别探究雄性繁殖成功的这两个组成部分，但极少有研究考察二者是否以及如何相互作用，进而决定整体性选择的强度。为解决这一研究空白，我们以锯缘果蝇（Drosophila serrata）为研究对象，对其领域行为展开探究——该物种中，雄性信息素（表皮碳氢化合物（cuticular hydrocarbons，CHCs））所对应的雌性偏好已被广泛研究。本研究证实，锯缘果蝇存在领域行为，该行为涉及直接的雄性间攻击互动，且其会导致雄性交配成功率产生变异。表型操作的实验结果同样表明，领域成功存在条件依赖性；不过一项通过三代全同胞近交实现的条件遗传操控实验，并未观测到显著效应。最后，选择实验结果还显示，雄性领域成功取决于其体型而非CHCs，而交配成功率的影响因素则恰好相反。