Evolved parental responses to offspring solicitation reflect energetic
demands, environmental predictability, and offspring predation risk
Abstract
Parental responses to offspring solicitation differ among species and
have major implications for fitness, but the evolutionary drivers of
this diversity are poorly studied. Here, we experimentally amplified
begging calls at nests of 25 songbird species in tropical and north
temperate communities. We analyzed parental provisioning responses using
phylogenetic path analysis to test the possible roles of demographic
(offspring predation or adult survival rates), ecological (food
predictability) or physiological (offspring energy need) traits in the
evolution of parental responsiveness to begging. Species with smaller
body mass, more unpredictable food availability, and greater offspring
predation rates were more responsive to begging. In contrast, we found
little support for direct effects of adult survival on parental
responses. Ultimately, the evolution of parental responsiveness to
offspring solicitation is strongly related to energetic needs of young
and the predation costs of begging.