Ma. Rodriguezgirones et al., INSTABILITY OF SIGNALING RESOLUTION MODELS OF PARENT-OFFSPRING CONFLICT, Proceedings of the National Academy of Sciences of the United Statesof America, 95(8), 1998, pp. 4453-4457
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.