Female mimicry in male bluegill sunfish—a genetic polymorphism?

Abstract

When male reproductive success depends on male–male competition and aggression, individuals which are at a competitive disadvantage sometimes adopt an entirely different constellation of reproductive behaviours. When such alternative reproductive patterns are practised opportunistically, as when a defeated territorial male adopts a parasitic role, or as part of a developmental sequence, as when younger males are satellites, they can be considered to be part of a single lifetime reproductive strategy. In contrast, when alternatives are available but individuals practise only a single reproductive option throughout their lifetime, the possibility of a genetic polymorphism can be considered. Such genetically mediated alternative reproductive strategies have been hypothesised¹, but the ontogeny of supposed alternative reproductive strategies is seldom known². This letter describes two reproductive patterns in bluegill sunfish (Lepomis macrochirus), a nesting male strategy and a female mimic strategy, and demonstrates that an individual male does not practise both reproductive strategies.