Mating without meeting

Choosing the right mate has important fitness consequences, especially for females. Typically, females choose their partner based on multiple sexual signals (visual, acoustic and chemical) provided by the male. However, several species have adopted a mating system of dissociated sperm transfer where males deposit their sperm in the environment for females to pick up, without any requirement for contact between males and females. Such dissociative systems are rather common among invertebrates, the dominant animal group in soil and marine environments. Yet, hardly anything is known about sexual selection with dissociated sperm transfer. Studies on the soil arthropod Orchesella cincta show that even in species with dissociated sperm transfer female mate choice exists. Moreover, females gain indirect benefits from choosing among the stalked sperm droplets (spermatophores) that males produce, showing that male quality is advertised by olfactory cues associated with the spermatophores. This project addresses a major question: can sexual selection drive the evolution of mating signals when females never meet their partners? To answer this question I investigate the sexual chemical communication system in O. cincta.