State-dependent mate-assessment and mate-selection behavior in female threespine sticklebacks (Gasterosteus aculeatus, Gasterosteiformes : Gasterosteidae)

Most investigations of mate-choice have focused on the outcomes of mate-cho ice (i.e. which mates are chosen), and thus we generally know very little a bout how mates are chosen (i.e. how mates are found, assessed, and selected ). Mate-choice by females has been shown to be dependent on the state of th e female, with females being less selective when limited by time or energy. This result could be caused by changes in female mate-assessment or mate-s election behavior. We examined whether manipulations of time and energy aff ected the mate-choice behavior of female threespine stickleback (Gasteroste us aculeatus). We found that female mate-choice behavior, when not divided into stages, was affected by both of the manipulations. This matches previo us findings. When we divided female courtship behavior into six stages, we found that the two manipulations affected different portions of the mate-ch oice process. The holding-time manipulation changed female behavior at the beginning and end of the mate-choice process and the swimming manipulation changed female behavior only at the end of the mate-choice process. Neither of the manipulations significantly affected female behavior in the middle portion of the mate-choice process. Thus, the mate-choice process appears t o be composed of multiple state-dependent decisions. We discuss how a bette r mechanistic understanding of how female state affects female mate-choice behavior can produce testable predictions and provide a basis for investiga ting the evolution of mating systems.