The bug spray on your bathroom shelf may not be working quite the way you think it does, and new research explains exactly why that might be happening.
A study published May 28, 2026, in the Journal of Experimental Biology by researchers from the University of Tours, France, and Virginia Tech found that Aedes aegypti mosquitoes — the species that transmits dengue fever, Zika virus, yellow fever, and chikungunya — can be conditioned to shift their behavioral response to DEET from aversion to attraction. In a form of Pavlovian learning, mosquitoes repeatedly exposed to DEET while feeding on warm blood came to associate the chemical's scent with a meal reward. In subsequent tests, those trained mosquitoes moved toward DEET-treated human skin rather than away from it.
