Data from: Sex-specific differences in the response of prey to predation risk

The nonconsumptive effects of predation risk can strongly affect prey
behavior and fitness with emergent effects on community structure and
ecosystem functioning. Prey may respond differently to predation risk
based on key traits such as sex, but the influence of sex-specific
variation is typically explored in species with strong sexual dimorphism.
However, sex-specific responses to predation risk may arise even in prey
species lacking sexual dimorphisms based on differences in the relative
cost of reproduction. Using a rocky intertidal food chain, we conducted a
laboratory mesocosm experiment to explore sex-specific responses of
morphologically similar, reproductively mature prey (the snail Nucella
lapillus) to predation risk and whether risk affected female fecundity. We
found that predation risk suppressed prey growth only in males via effects
on growth efficiency, suggesting that sex-specific disparities may arise
due to differences in the energy required for reproduction and/or the
costs of mounting a physiological stress response. Moreover, while risk
did not affect overall female fecundity, it eliminated the positive
relationship between female size and fecundity observed in the absence of
risk. We hypothesize that these sex-specific disparities arise due to
differences in the energy required for reproduction and/or the costs of
mounting a physiological stress response. Reproduction is likely more
costly for females than males, so females may display weaker antipredator
responses in order to maintain energetic reserves needed for reproduction.
Our results suggest that sex-specific responses may be an important
component of inter-individual differences in prey responses to risk and
influence prey population growth and demography even in species lacking
sexual dimorphism.