A fundamental question in biology is how organisms adapt to changes in their environment or in their social groups in ways that lead to the creation of new species. A novel hypothesis about how this may happen states that when females choose attractive mates they may also favor mates that are well-adapted to their environment. This is because mate-attraction displays can be costly to produce, so that only males that are well-adapted to an environment may be capable of producing attractive displays. Mate choice may thus create an association between attractiveness and local adaptation, and promote divergence when occurring in different environments. This study will test this hypothesis by evaluating the quantitative genetics of behavioral and life history traits in a group of plant-feeding insects. A sample of families will be reared on native environments (to which they are adapted), and on novel environments. The expectation is that in the native environment attractive males will have the highest performance, but this relationship should break down in novel environments. By potentially reconciling the ability of mate choice to promote rapid diversification with the ability to create ecological differences, this research may transform how biologists view two of the most basic evolutionary processes: adaptation and divergence. Other broader impacts of this study include training in research, mentorship, and outreach for students at undergrad, grad, and postdoctoral levels.