When their ranges overlap—such as in Florida, where both are invasive—the Asian tiger mosquito (Aedes albopictus, left) and the yellowfever mosquito (Aedes aegypti, right) mate but produce no offspring, in an event known as satyrization. They can evolve over the course of a few generations to learn to avoid each other, but that choosiness may cost the mosquitoes in other ways. New studies by researchers at the University of Florida and Brazil’s Oswaldo Cruz Institute shed more light on evolved resistance to satyrization and its potential costs. (Photo credits: James Gathany, CDC Public Health Image Library)