INSTABILITY OF SIGNALING RESOLUTION MODELS OF PARENT-OFFSPRING CONFLICT

Recent signaling resolution models of parent-offspring conflict have p rovided an important framework for theoretical and empirical studies o f communication and parental care. According to these models, signalin g of need is stabilized by its cost. However, our computer simulations of the evolutionary dynamics of chick begging and parental investment show that in Godfray's model the signaling equilibrium is evolutionar ily unstable: populations that start at the signaling equilibrium quic kly depart from it. Furthermore, the signaling and nonsignaling equili bria are linked by a continuum of equilibria where chicks above a cert ain condition do not signal and we show that, contrary to intuition, f itness increases monotonically as the proportion of young that signal decreases. This result forces us to reconsider much of the current lit erature on signaling of need and highlights the need to investigate th e evolutionary stability of signaling equilibria based on the handicap principle.