Fruit Flies Reveal How Insect Resistance Evolves New research that explores how the gene for resistance to DDT functions in fruit flies has implications for pesticide development. The investigation centers on a type of "sexually antagonistic" gene that increases female resistance but decreases male hardiness when encountering DDT. Females do better than males when exposed to DDT, causing Drosophilia to select for certain traits in females that are more advantageous to them than to males. But this selection supports genetic variation, helping the species in the long run of evolutionary fitness. Sexually antagonistic selection thus helps maintain genetic variation in the natural world. DDT is prohibited as a pesticide for every day use, but is sometimes a weapon against disease-carrying insects like mosquitoes in cases where public health is an issue. It might be sprayed to prevent outbreaks of malaria, for example. Knowing how insects adapt and evolve when exposed to pesticides is important in understanding the way to optimize new pesticide compounds. This study illuminates how an insect resistance system can also benefit the species. Working at the Centre for Ecology and Conservation at the University of Exeter's Cornwall Campus in Penryn, Professor David Hosken explained: "Our results show the potential value for insect resistance systems to not only play a part in applied pest management but also shed light on fundamental evolutionary questions."