Condition-dependent female chemical signals and adaptive male mate choice in the sexually cannibalistic spider Argiope bruennichi
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.
PIs: Jutta Schneider, Katharina Weiss
- Duration: 2019 - 2022
- Sponsor: DFG