Bring on the bug zappers.

DEET, a chemical found in most bug sprays, repels mosquitoes by mimicking plant chemicals.

When female mosquitoes go out looking for blood—which they need to fertilize their eggs—they're not interested in plants. So a DEET-coated human doesn't smell like a tasty snack, according to study co-author James Logan, a chemical ecologist at the U.K. agricultural-research center Rothamsted Research.

But in recent tests, researchers identified some DEET-insensitive Aedes aegypti mosquitoes—a species that carries the diseases dengue and yellow fever—by observing which insects bit DEET-treated human arms. The team then discovered that a gene alteration stopped a sensory cell on the bugs' antennae from detecting