Mosquitoes Learn to Like DEET: Repellent May Become Attractant, Study Finds

Scientists reveal that mosquitoes learn to like DEET after repeated exposure, turning the world‑widely used repellent into a potential lure. In a study published in the Journal of Experimental Biology, researchers at Virginia Tech demonstrated that when the scent of DEET fades but does not disappear, the insects associate it with a blood meal and return in force.

mosquitoes learn to like DEET – behavioral conditioning explained

The experiment placed Aedes aegypti in a glass tube with a warm blood source behind a mesh. After feeding, the insects were exposed to DEET; they continued to feed despite the odor. When the blood was removed but DEET remained, ↑ 60% of the mosquitoes revisited the mesh, expecting a meal.

“Mosquitoes are very plastic. They can turn an aversive molecule into an attractant,” says associate professor Clément Vinauger.

A second trial offered two human hands, one treated with DEET. Trained insects attacked both hands, while naïve ones avoided the treated hand. The pattern held when sugar replaced blood, confirming that the chemical can act as a “dinner bell” after conditioning.

These findings do not render DEET useless; the repellent remains effective when applied at the recommended concentration and reapplied regularly. Vinauger advises frequent, thin applications rather than a single heavy dose, to keep skin concentrations above the aversive threshold.

Public‑health experts still champion classic defenses: screened windows, bed nets in malaria‑endemic regions, removal of standing water, and the use of octenol traps. For a broader perspective on vector‑borne disease trends, see Reuters and AP News. The ongoing pandemic has underscored the importance of robust mosquito control strategies worldwide.

Analysis by Elena Rostova (Socio-Economic Trends Analyst).