Amino Kai, Matsuo Takashi
Laboratory of Applied Entomology, Department of Agricultural and Environmental Biology, The University of Tokyo, Japan.
Laboratory of Applied Entomology, Department of Agricultural and Environmental Biology, The University of Tokyo, Japan.
Behav Processes. 2023 Mar;206:104831. doi: 10.1016/j.beproc.2023.104831. Epub 2023 Jan 21.
In the resource-defence mating system, where males compete for limited resources to acquire females, male traits associated with fighting ability are selected, leading to the evolution of sexual dimorphism. However, the evolution of sexual dimorphism is also driven by other mechanisms, such as female selection. Therefore, to elucidate the evolutionary mechanisms of male traits, it is necessary to clarify their contribution to fitness through male-male competition. In this regard, it is surprising that numerous studies on sexually dimorphic species have assumed the resource-defence mating system without directly examining the relationship between resource-defending behaviour and mating success. In a sexually dimorphic fruit fly, Drosophila prolongata, the presence of the resource-defence mating system has been suggested, but technical difficulties had prevented spatial quantification of the resource-defending behaviour. In this study, by using an automated behaviour analysis tool previously developed, we located the occurrence of male-male competition and courtship to investigate their relationship in D. prolongata, considering the position of food resources. We found that the male-male competition led to the exclusive occupation of resources, increasing the courtship opportunities of the resource holders. These results illustrate the importance of resource-defending for reproductive success in D. prolongata.
在资源防御交配系统中，雄性为获取雌性而争夺有限资源，与战斗能力相关的雄性特征会被选择，从而导致两性异形的进化。然而，两性异形的进化也受其他机制驱动，比如雌性选择。因此，为阐明雄性特征的进化机制，有必要通过雄雄竞争来明确它们对适应性的贡献。在这方面，令人惊讶的是，众多关于两性异形物种的研究都假定了资源防御交配系统，却未直接考察资源防御行为与交配成功之间的关系。在一种两性异形的果蝇——长果蝇（Drosophila prolongata）中，有人提出存在资源防御交配系统，但技术难题阻碍了对资源防御行为进行空间量化。在本研究中，我们使用先前开发的自动行为分析工具，结合食物资源的位置，确定了长果蝇中雄雄竞争和求偶行为的发生情况，以研究它们之间的关系。我们发现，雄雄竞争导致资源被独占，增加了资源占有者的求偶机会。这些结果说明了资源防御对长果蝇繁殖成功的重要性。
