Signaling of Need between Parents and Young: Parent-Offspring Conflict and Sibling Rivalry

Abstract

The young of birds and mammals frequently solicit food and other resources from their parents in ways that appear to be costly either in terms of energetic expenditure or because they may attract predators. Costly solicitation has been explained as a means by which the young manipulate their parents into providing more resources than the parental optimum. Alternatively, communication between parents and young can be interpreted as an evolutionarily stable signaling system. A model is developed of two young in a brood who compete for a fixed amount of resources distributed by their parents. It is shown that an evolutionarily stable signaling system can exist in which the parent obtains accurate information about the resource needs of its young and on which it bases its resource distribution decisions. Young with greater resource requirements solicit at higher levels, but the system is stable because any misrepresentation is selected against. Essential for stability is that signaling must be costly; it is t...