Female Preference Functions Provide a Window into Cognition, the Evolution of Communication, and Speciation in Plant-Feeding Insects

Abstract

AbstractWhen female mate choice is based on male signals, female responses can be characterized in the form of preference functions that relate signal variation to attractiveness. Within a population, male displays will vary in multiple dimensions; preference functions reveal which of these dimensions are important for female mating decisions, suggest how sensory information is processed, and allow us to make predictions about the relationship between male signal variation and fitness. Here we discuss how characterizing female preference functions helps us understand the process of diversification in plant-feeding insects, an important component of terrestrial biodiversity. In the clade of insects we are studying, speciation is initiated by a shift from one host plant species to another. Host shifts lead to changes in the timing and location of mating, but the evolutionary changes that occur in mating signals and preferences are just as important for reducing gene flow among populations on different hosts. We focus on a subset of male signal traits for which female preference functions differ in strength and shape, and explore the effect of female preferences on male fitness within a population and on reproductive isolation among species. Integration of studies in the laboratory and field reveal how preference functions provide insights into the cognitive processes underlying mate choice, as well as the evolutionary forces that shape signal evolution.