Begging signals and parent–offspring conflict: do parents always win?

Abstract

Apparently costly begging behaviour has recently been explained as a means by which offspring communicate their need, allowing parents to provide them with a level of resource equal to that which would be optimal (for the parents) in the absence of begging. This hypothesis contrasts with earlier explanations, which suggest that solicitation induces parents to provide more resources than it would otherwise (in the absence of begging) be optimal for them to do. Here, I develop an extended model of costly begging as a signal of need, which unlike previous analyses allows offspring to adjust their level of begging over time in response to parental feeding. I show that under these more realistic conditions, a signalling resolution of parent-offspring conflict also leads parents to allocate more resources than would otherwise be optimal for them, in order to reduce the subsequent level of costly solicitation by their young.