Journal Paper Title of the Day
Nathan W. Bailey, "Love will tear you apart: different components of female choice exert contrasting selection pressures on male field crickets", in Behavioral Ecology, Vol. 19, No. 5, September-October 2008, pp. 960–966. [URI]
Theory predicts that exaggerated male ornaments can evolve through the action of female choice for those ornaments. Female choice consists of the preferences that females exert, which can be characterized by functions describing how the probability of mating relates to variation in male traits. In addition, females can vary in how responsive they are to male mating signals either by adjusting how many potential mates they respond to or by altering the effort, or speed, of their response. Discrimination describes how strongly females distinguish between male trait values. Little is known about how these behavioral components interact to produce final mating decisions, but such information is necessary to better understand the behavioral basis of male ornament evolution. I performed mate choice experiments using the field cricket, Teleogryllus oceanicus, and found that individual females varied widely in the shape of their preference functions for male song traits. Some components of female choice appeared to be behaviorally linked: more responsive females were more discriminating, but only when response likelihood was considered. Discriminating females were also more likely to show stabilizing preference functions favoring intermediate male trait values. Finally, I used two methods to construct population-wide preference functions with pooled response data from all females. The first method used female response likelihood as a proxy for female mating probability and generated a strongly linear function that favored extreme male song values. The second method used female response effort as a proxy for mating probability and revealed a strongly stabilizing function that favored intermediate trait values. The outcome of female choice in a wild setting ultimately depends on the relative importance of response number versus response effort, where exogenous factors such as predation risk or density will determine which component of female choice predominates mating decisions.