Study finds Aedes aegypti can learn to seek DEET scent

A new study reveals that mosquitoes can learn to associate the common insect repellent DEET with a food source, potentially altering their innate aversion to the chemical. The research, published in the Journal of Experimental Biology, demonstrates that under specific laboratory conditions, yellow fever mosquitoes (Aedes aegypti) can be conditioned to treat the repellent's scent as a signal for a meal.

Scientists from Virginia Tech in the United States and the University of Tours in France used a Pavlovian conditioning approach. They exposed female Aedes aegypti mosquitoes, a primary vector for diseases like dengue, Zika, and yellow fever, to the smell of DEET while they fed on warm blood or sugar. After several repetitions, more than 60 percent of the conditioned mosquitoes attempted to feed when presented with the scent of DEET alone, a stimulus they would normally avoid.

In a further test, researchers offered the mosquitoes a choice between a human hand treated with a standard concentration of DEET and an untreated hand. While untrained mosquitoes avoided the DEET-coated hand, the conditioned mosquitoes were attracted to it, indicating a learned behavioral shift.