Effects of chronic and acute predation risk on sexual ornamentation and mating preferences

We examined how chronic and acute predator presence affects the expression of male traits and female choice in three-spined stickleback. Males reared in the presence of a predator cue showed reduced breeding colouration, but higher courtship activity, while acute predator presence had no influence. Predator presence during development did not affect female choice, while acute presence changed female preferences. Predator-induced plasticity in male traits and female preferences therefore lead to dynamic processes that alter sexual selection. Phenotypic plasticity is widespread in animals. Still, how plastic responses to predator presence affect traits under sexual selection and influence mating preferences is not well understood. Here, we examined how simulated chronic predator presence during development and acute predator presence during mate choice affect the expression of male secondary sexual traits and female mating preference in the three-spined stickleback, Gasterosteus aculeatus. Males reared under chronic predator presence developed less intense red breeding coloration but showed higher courtship activity than males that grew up in a predator-free environment. Acute predator presence during mate choice trials did not influence male behavior or ornamentation. Predator presence experienced during development did not affect female mating preferences, whereas acute predator presence altered preferences for male courtship activity. Male body size and eye coloration influenced the intensity of female mating preferences, while the trait changing most in response to predator presence during development (red coloration) had no significant impact. The observed interplay between developmental plasticity in male ornamental traits and environment-dependent female mating preferences may lead to dynamic processes altering the strength and direction of sexual selection depending on both the chronic and acute risk of predation. These processes may contribute to the maintenance of within- and among-population variation in secondary sexual traits, and may, ultimately, facilitate speciation.