Mosquitoes adapting to common insect repellent as disease risk concerns grow
The Mirror
Last updated: June 5, 2026
A new study suggests that mosquitoes can learn to associate the smell of DEET, a common insect repellent ingredient, with food. This learned attraction could potentially challenge the perceived effectiveness of DEET as a deterrent, especially as mosquito-borne diseases pose a significant global health threat.
- Researchers utilized Pavlovian conditioning to demonstrate this phenomenon in yellow fever mosquitoes (Aedes aegypti). By repeatedly exposing mosquitoes to the smell of DEET while they were feeding on warm blood, the insects eventually began to associate the chemical scent with a food reward.
- Following this conditioning, mosquitoes showed a significant attraction to the smell of DEET, even attempting to feed on a hand coated in the repellent. This suggests that in certain conditions, DEET might not only fail to repel but could inadvertently attract mosquitoes that have previously learned this association.
- The study's findings indicate that DEET's effectiveness might diminish with repeated exposure, potentially making individuals who applied repellent hours earlier, when the concentration is lower, more attractive targets. However, researchers still acknowledge DEET as a highly effective repellent for preventing mosquito-borne diseases, recommending regular reapplication for continuous protection in high-risk areas.
