A major focus of recent work on animal mating systems has been to understand why females typically mate with many different males (polyandry). An emerging consensus is that females mate polyandrously to secure genetic benefits for their young. If this is true, we might expect females to forego mating with previous partners in favor of novel males, and indeed, a female preference for novel mating partners has been demonstrated in several species. But how do females distinguish among novel males and previous mating partners? Preliminary results based on cricket research suggest that females do so by "tagging" males with their own odors during mating. When a female encounters a former mating partner later on, she need only compare her own scent with that of the male. If she finds that the male has been imbued with her own chemical signature, she can avoid mating with that male in favour of a novel mating partner. This mechanism, known as the "armpit" effect, may provide females with a simple, but reliable means of identifying individuals with whom they have mated without requiring any special cognitive ability. This type of simple self-referencing could be a fairly common mechanism by which females across a broad range of animal mating systems increase the diversity of their mating partners, and thereby maximize the genetic benefits of polyandry. NSF support will be used to initiate measurements of females from genetically inbred lines to characterize genetic variation in cuticular hydrocarbons, the chemicals that are the most likely source of the odors used in self-recognition. If females rely on cuticular hydrocarbons to recognize previous mates, we would expect different females to express different chemical signatures. This represents a critical first step towards achieving the aims outlined in the parent proposal because genetic differences in cuticular hydrocarbon profiles lies at the crux of the proposed mechanism. Broader impacts of the proposed research include opportunities to enhance the professional growth and development of several undergraduate and graduate students, and will help redress the current under-representation of women in science. There is a commitment in the two research labs to the principle that a sound undergraduate education in science can only come about through the direct involvement of undergraduates in research. A large proportion of undergraduates are already involved in faculty research projects at some point in their training, and graduate students are strongly encouraged to disseminate the results of their work, both at professional meetings and to the lay public. For example, in addition to regular participation at national/international meetings and publication in prestigious journals, graduate students and the two mentors have been active in programs designed to enhance elementary school teachers' training in science and to mentor female high school students. Overall these activities will be continued and expanded during the course of this research project.
