Since 2008 Leslie Vosshall, director of the Vosshall Laboratory at Rockefeller University, has been working on making a better mosquito repellent than DEET. In this Atlantic article by Ed Yong, she explains why it's so hard to keep the tiny vampires from sucking our blood.
"Narrowly focusing on a single sensory pathway to stop mosquitoes is doomed," she says, because they track their prey with so many different cues. "It's an incredibly smart strategy. From the mosquito's point of view, there are a lot of unreliable signals in nature, so they integrate multiple pathways. They have a Plan B at every point."