The Evolution of Reliable and Unreliable Badges of Fighting Ability

Abstract

SYNOPSIS. When a population may be characterized by interference competition for resources, variation in fighting ability among individuals, and repeated confrontations between individuals, together with difficulty of individual recognition, badges of status should invade as recognition marks that render good fighters memorable. Reliability of such badges can be maintained by negative frequency-dependent selection when individuals of different appearance (and status) either play mutually beneficial roles or employ alternate competitive tactics. In territorial social systems intraspecific mimicry of recognition badges should evolve because, in contrast to group-living situations, the cost to a cheat of being discovered is low when individuals are dispersed. The general result of such mimicry is that good and poor fighters become similar in appearance. From the theoretical treatment of status recognition badges I derive a number of predictions that pertain both to interand intraspecific differences in conspicuous coloration and to the evolution of local song dialects in birds.