Researchers have identified a mating mechanism that possibly could be adapted to prevent female mosquitoes from spreading the viruses that cause dengue fever, second only to malaria as the most virulent mosquito-borne disease in the tropical world. Specifically, they have discovered 63 proteins that male mosquitoes transfer to mosquito females during mating and are thought briefly to change the females’ physiology and behavior, in particular suppressing the female’s appetite for mammalian blood.