Traditionality of mating-site preferences in a coral reef fish

Abstract

Mating systems are often viewed as a result of females choosing where, when and with whom to mate^1,2, and of male responses to female behaviour^3,4. If the distribution of females reflects their response to vital resources for survival and reproduction, then a careful study of these resources should yield predictions about the emergent mating system. Males and females could, however, simply gather at traditional sites to mate⁵. If so, analysis of the current state of the environment may yield incorrect predictions about mating sites^5–9. Mating sites of the bluehead wrasse Thalassoma bifasciatum have remained in daily use over 12 years (four generations) without changing locations. Here, I show that experimental replacement of entire local populations led to the use of new sites, which continued to be used after the manipulations. Thus mating site locations may not be the result of individual assessment of current resource quality, but instead represent culturally transmitted traditions. Attempts to explain mating patterns based on the distribution of resources should therefore be approached with caution.