The degree of response to increased predation risk corresponds to male secondary sexual traits

Secondary sexual traits are expected to reflect a balance between sexual selection and natural selection. We test the hypothesis that plasticity in sexual advertisement behaviors can influence this trade-off, allowing showier traits than expected for a given level of predation risk. Specifically, we tested whether the degree of behavioral plasticity exhibited in response to chemical cues of a co-occurring predatory wolf spider corresponds to courtship rate and the degree of ornamentation in male wolf spiders. Both ornamented (brush-legged) males and non-ornamented males decreased locomotion, decreased their likelihood to court, and increased their time to initiate courtship in response to predator cues. However, brush-legged males increased their time to initiate courtship more than did non-ornamented males, demonstrating a greater response to the risk of predation for the more ornamented males. Similarly, within brush-legged males, individuals with the highest courtship rates also showed the greatest degree of plasticity in time to initiate courtship across predation contexts, whereas behavioral plasticity was independent of courtship rate for non-ornamented males. We found no correlation between ornament size and plasticity in response to predator cues within brush-legged males. Ultimately, we suggest that our data provide support for the hypothesis that behavioral plasticity in response to predator cues may alter the trade-off between predation risk and sexual advertisement and may be more important for males with higher degrees of conspicuousness in ornamentation and courtship. Copyright 2011, Oxford University Press.