You may be surprised to learn that what you thought were blood-thirsty mosquitoes aren't always thirsty for blood. The most important sustenance for a mosquito is actually sugar. In fact, only female mosquitoes suck blood, but they need sugar more often, and male mosquitoes subsist entirely on sugar. Mosquitoes can usually get their sugar fix from plants and flowers, and researchers at the U.S. Department of Agriculture have found that using sugar traps is the most effective way to lure in the pesky insect. Knowing about the mosquito's sweet tooth, researchers mix a toxic insecticide into a sugar-based solution to attract and kill them. This method could help reduce the spread of mosquito-borne illnesses.