Sexual pigmentation and parental risk-taking in yellow warblers Setophaga petechia
Andrea S. Grunst, Melissa L. Grunst, John T. Rotenberry
Adult-directed predation risk imposes important behavioral constraints on parents and might thus alter relationships between costly sexual ornaments and parental performance. For instance, under low predation risk, highly ornamented individuals might display better parental performance than others, as predicted by ‘good parent’ models of sexual selection. However, under high risk of predation, highly ornamented individuals might abandon parental effort if conspicuous to predators, or if social partners are more willing to take parental risks when paired with highly ornamented mates. We experimentally elevated perceived adult-directed predation risk near nests to explore how carotenoid- and phaeomelanin-based pigmentation in both sexes relate to parental risk-taking for offspring in the yellow warbler Setophaga petechia. Compared to other males, males with more intense carotenoid-based pigmentation maintained higher levels of paternal effort under predation risk at highly concealed nests, but reduced nestling provisioning rate more at exposed nests. Further, when faced with predation risk, females with more phaeomelanin-based pigmentation reduced nestling provisioning rate less than other females, regardless of nest concealment. Females displayed higher parental effort across treatments when paired to males with more colorful carotenoid pigmentation. However, birds did not reduce parental effort under risk less when paired to a highly ornamented mate, suggesting that predation risk did not accentuate differential allocation. Males did not take fewer parental risks than females. Results indicate that nest concealment modifies parental risk-taking by males with colorful carotenoid-based pigmentation, and suggest that female melanin-based pigmentation may indicate boldness and greater a propensity to take parental risks.