Sexual traits such as courtship displays are often the most diverse features among closely related species. Understanding the origin and maintenance of diversity in nature thus requires understanding sexual selection (competition for mates and their gametes). Its basic mechanism hinges on the genetics of sexual traits, and recent findings about their genetic architecture are revolutionizing the field. This project will provide the most comprehensive information to date on the reaction norms of sexual traits (reaction norms are curves that show the forms that individuals of the same genotype can take in different environments). Different patterns in the reaction norms of male and females may have different consequences for sexual selection, all the way from hindering the process to initiating and promoting divergence. But we do not have enough data to assess which outcomes are common. This project will provide the foundation for making this assessment. This requires a study group in which sexual selection and environmental variation are known to influence divergence. This is the case in Enchenopa treehoppers, which are plant-feeding insects that communicate with vibrational signals (sounds that travel through plant stems.) Research methods involve quantitative genetics (in which breeding designs are used to estimate genetic parameters, as for example with cattle), and state-of-the-art laser vibrometry to monitor vibrational communication. This project will broaden the participation of under-represented minorities in science, and integrate research, teaching and outreach activities. Junior participants will be exposed to positive role models while more senior participants train in providing mentorship. The project will take advantage of Milwaukee's Urban Ecology Center to present core findings to the public in lectures and field activities.
Intellectual merit: How biologists view the origin of species and adaptation to novel environments is being transformed by discoveries about the patterns of variation in mating signals and mate preferences that are common in natural populations. One of these discoveries is genetic variation in how traits change between environments: mating signals and preferences often differ between populations in different environments, and recent work has revealed genetic variation in those differences. This project involved the most comprehensive measure to date of these patterns of genetic variation in mating signals and preferences, with the overall goal of contributing to a new vision of the origin of species and of adaptation to novel environments. Outcomes include: one of the most detailed assessments to date of the consistency of variation between individual females in their mate preferences; a new conceptual framework for understanding the evolution of between-environment differences in mate preferences, with empirical tests of the framework; and the beginning of a data set comparing these patterns between mating signals and mate preferences. Broader impacts: Activities focused on providing extensive training in research and in mentorship to a diverse team of undergratuate, graduate and postdoctoral students. This training includes data analysis, preparation and submission of scientific papers, and numerous presentations at national-level scientific conferences. Additional activities include public outreach and invited university presentations by the principal investigator and a graduate student.
