How can Honest Signalling Evolve? The Role of Handicap Principle

Shigeo Yachi


Handicap principle is now widely accepted as a mechanism for maintaining honest signalling. However, little attention has been paid to how honest signalling evolves in the first place. Using a model of predatorprey interaction with two levels of prey's quality and signalling intensity, I examine the conditions for the evolution and maintenance of honest signalling and, in particular, elucidate the role of handicap principle. Major conclusions are as follows. 1. Prey's honest signalling can be maintained only if predators prefer prey of weak (or no) signalling. 2. Predator's preference of no-signalling prey is also prerequisite for the evolution of honest signalling from no signalling. 3. This predator's preference may evolve from no preference, by genetic drift or pleiotropy. 4. Once predator's no-signalling preference is in place, honest-signalling prey can invade and take over no-signalling ones under certain conditions. These conditions are more strict than those for honest-signalling maintenance. 5. Both conditions commonly imply that signalling pays (i.e. signalling cost should be smaller than the predation cost which must be paid for not signalling) for high escaping-ability prey whereas it doesn't for low escaping-ability one, articulating a form of handicap principle.