Condition-dependent female chemical signals and adaptive male mate choice in the sexually cannibalistic spider Argiope bruennichi

信息素是一种化学物质，在物种内的个体之间传递信息。特别是在节肢动物中，化学信号是普遍的通信手段，特别是在性通信中。男性信息素在女性择偶的背景下进行了很好的研究。然而，同样普遍发生的男性择偶的基础上，女性的化学线索，直到最近才被承认和理解女性性信号的演变和适应性男性择偶决定的标准是性选择研究的最后空白点之一。一般来说，只有当（1）选择的收益大于成本，（2）当雌性的质量发生变化时，雄性选择性的进化和交配策略的有条件调整才是有利的。这两个条件在圆网蜘蛛Argiope bruennichi身上都得到了满足。该物种的雄性交配率非常低，因此与低质量的雌性交配严重影响了一生的生殖成功。此外，雌性在生殖力方面差异很大。行为分析表明，雄性会根据雌性的交配状态、年龄和体型来调整它们的交配行为，它们最有可能通过化学线索来评估这些行为。因此，作为首次在蜘蛛中进行这方面的研究，我们建议将联合收割机化学生态分析和行为学测定相结合。bruennichi，以扩大我们的知识，条件和状态依赖的变化，女性性信号和他们的功能，在男性择偶。我们假设雌性A. bruennichi包含条件依赖性信息，雄性利用雌性化学特征的变化来做出适应性交配决定。具体而言，本项目将调查（1）基于女性化学线索变化的男性择偶，（2）挥发性女性线索在择偶评估中的作用，以及（3）女性是否可以调整其信号努力以最大化其健身回报。

Pheromones are chemical substances that transmit information between individuals within a species. Particularly in arthropods, chemical signals are the prevalent means of communication, especially in sexual communication. Male pheromones in the context of female mate choice are well studied. Yet, the likewise widespread occurrence of male mate choice based on female chemical cues has only recently been acknowledged and understanding the evolution of female sexual signals and the criteria underlying adaptive male mate choice decisions is one of the last blank spots of sexual selection research. Generally, the evolution of male choosiness and the conditional adjustment of mating tactics are favored only if (1) the benefits of choosing exceed the costs and (2) when females vary in quality. Both conditions are met in the orb-web spider Argiope bruennichi. Males of this species have very low mating rates, hence mating with low-quality females critically affects life-time reproductive success. Moreover, females vary considerably in fecundity. Behavioral assays show that males adjust their mating behavior depending on female mating status, age and size, which they most likely assess via chemical cues. Therefore, as the first study to this aim in spiders, we propose to combine chemical-ecological analyses and behavioral assays on A. bruennichi to broaden our knowledge on condition- and state-dependent variation of female sexual signals and their function in male mate choice. We hypothesize that the chemical profiles of female A. bruennichi contain condition-dependent information and that males use variation in the chemical profiles of females to make adaptive mating decisions. Specifically, this project will investigate (1) male mate choice based on variation in female chemical cues, (2) the role of volatile female cues in mate assessment, and (3) whether females can adjust their signaling effort to maximize their fitness returns.