Subverting Cognition! Experiments Prove Mosquito Brains, When Trained, Prefer Biting Those Sprayed with Repellent

In a surprising turn of events, new research suggests that mosquitoes can be trained to associate the smell of DEET, the world's most common insect repellent, with a satisfying meal. The study, published in the Journal of Experimental Biology, found that after a learning process, mosquitoes actually developed a preference for biting those who had been sprayed with DEET.

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We show that the mosquito brain can rewrite this response based on experience.

Claudio Lazzari, a professor at the University of Tours and lead author of the study, clarified that these findings, obtained under "very specific laboratory conditions," do not question DEET's overall effectiveness. Since its development in the 1940s, DEET has been a crucial tool in preventing mosquito-borne diseases like dengue, Zika, and malaria, recognized by the World Health Organization.

However, the research delves into the 'why' behind mosquito aversion to DEET. Scientists employed a Pavlovian conditioning approach, similar to how dogs learn to associate a bell with food. In the experiment, mosquitoes were exposed to the smell of DEET for a short period immediately after feeding on warm blood. Repeated trials led to over 60% of the trained mosquitoes attempting to bite a net containing the DEET scent, even without a blood source present.

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What insects learn is as important as how the chemicals work. I think this is a paradigm shift.

Further tests showed these conditioned mosquitoes preferred a hand treated with DEET over a clean one. The researchers, including Clement Vinauger from Virginia Tech, suggest that for mosquitoes, the reaction to DEET might not be solely due to its chemical toxicity but rather how their brains interpret the chemical information. This "paradigm shift" indicates that a mosquito's brain can rewrite its response based on experience, highlighting that learned behavior is as significant as the chemical's properties.

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although mosquitoes were trained relatively quickly in the experiment, in nature, 'very specific conditions are needed for things to happen in the same way.'