How does sexual selection contribute to biodiversity on earth? ASTRID T. GROOT investigates this question using the example of moths. As she explains in this video, in many species, including moths, the most common individuals are chosen as mates and the ones that deviate away from the mean are selected against. Following this principle, you would expect less and less variation but this is not the case. Thus, her research team examines how genetic variance is maintained. They analyzed the mechanism underlying signal variation and response variation and questioned the general assumption that the average is always chosen over the extremes. After detailed behavioral analysis in the laboratory and the field they found that the signaling itself changes and that, indeed, the most common individuals are not always chosen. These findings add to a better understanding of how sexual selection and its evolution might drive diversity.