Anopheles darlingi mosquitoes—a major vector of malaria in South America—are evolving in response to insecticides, which may make them harder to kill and malaria more difficult to control, according to a new study led by Harvard T.H. Chan School of Public Health. The study appears in Science. It is the first study to sequence a large number (>1000) of complete genomes of Anopheles mosquitoes in the Americas, where there are more than 600,000 cases of malaria annually, mostly in Brazil, Colombia, and Venezuela.