Evolution of mate harm resistance in females from Drosophila melanogaster populations selected for faster development and early reproduction.

Abstract

Interlocus sexual conflict is predicted to result in sexually antagonistic coevolution between male competitive traits, which are also female-detrimental, and mate harm resistance (MHR) in females. Little is known about the connection between life history evolution and sexually antagonistic coevolution. Here, we investigated the evolution of MHR in a set of experimentally evolved populations, where mate-harming ability has been shown to have substantially reduced in males as a correlated response to the selection for faster development and early reproduction. We measured mortality and fecundity in females of these populations and those in their matched controls under different male exposure conditions. We observed that the evolved females were more susceptible to mate harm-suffering from significantly higher mortality under continuous exposure to control males within the 20-day assay period. Though these evolved females are known to have shorter lifespan substantially higher mortality was not observed under virgin and single-mating conditions. We used fecundity data to show that this higher mortality in the experimentally evolved females was not due to the cost of egg production and hence can only be attributed to reduced MHR. Further analysis indicated that this decreased MHR is unlikely to be due purely to the smaller size of these females. Instead, it is more likely to be an indirect experimentally evolved response attributable to the changed breeding ecology and/or male trait evolution. Our results underline the implications of changes in life history traits, including lifespan, for the evolution of MHR in females.