Mosquitoes can become attracted to insect repellant, study suggests

The insect may learn to associate the chemical Deet with a ‘blood meal’, researchers say It is a spray used worldwide to protect humans from mosquito bites, but now research suggests Deet can become attractive to the insects if they associate it with feeding. Deet – which has the chemical name N,N-diethyl-meta-toluamide – is widely used in insect repellants, with the UK Health Security Agency recommending products with 50% Deet as the first choice to protect against mosquito bites. Such protection is important given that in some countries mosquito bites can spread fatal diseases such as dengue, Japanese encephalitis, malaria and Zika. However, a new study suggests that, as Pavlov’s dogs learned to associate the ringing of a bell with food, so mosquitoes can learn that the presence of Deet indicates the possibility of a blood meal. “For a long time, it was believed that repellants worked solely because of their chemical properties, either by being toxic or unpleasant to mosquitoes and driving them away, or by blocking their ability to detect humans. However, our findings suggest that the reaction can be modified by experience,” said Prof Claudio Lazzari, from the University of Tours