Summer is practically upon us and this means that mosquitoes are also beginning to be the order of the day. Here one of the great allies we have to spend a good night is the repellent that keeps mosquitoes away from our skin, but the problem is that now these little insects seem to have unlocked a new and disturbing achievement: relating repellent to the best place to bite.
A new problem. A recent study published in the magazine Journal of Experimental Biology points out that the classic repellent made up of the synthetic molecule N,N-Diethyl-meta-toluamide It has stopped repelling mosquitoes and started attracting them.
In this study, the researchers focused on the Aedes aegyptithe infamous mosquito yellow feverdengue and Zika. From here, what they did was design a highly controlled laboratory environment with meshes, heat sources that simulated human warm blood or sugar rewards. But they combined all these ideal conditions with the presence of the smell of repellent.
The result. From several cycles of exposure to these environmental conditions, they could see that mosquitoes had the ability to learn and create an association between the repellent and the presence of a good place to bite.
This means that if a mosquito dares to cross the barrier left by the repellent and manages to bite, or feed on sugar in this case, its brain is reprogrammed and the repellent goes from being a “danger” signal to a “there is food here” signal. In fact, the data showed that, after this conditioning, more than 60% of mosquitoes They went back to searching for the smell of the repellent, ignoring its original repulsive nature.
It takes years. Although the jump to “attraction” is novel, the reality is that entomologists have been keeping the fly behind their ears for some time. Without going any further, in 2013 a study already showed that mosquitoes developed tolerance to repellents. In this case, it was found that three hours after a first exposure to DEET, the insects ignored the repellent. And now we know a little more about what exactly happens neurobiologically.
You have to use it well. These results have occurred in a very controlled environment and forcing scenarios that are very specific with guaranteed rewards. But in the real world we find greater chaos and a mosquito that smells the repellent and cannot bite, because the concentration is high, it does not receive the “reward” of blood, so that learning is not consolidated.
That is why researchers point to the need for the repellent to be applied within the time frame and in adequate concentration. But this does not mean that we do not have to redesign public health strategies adapting them to this plasticity that mosquitoes have, since we are not just talking about an annoying bite, but we are talking about the fact that the mosquito is a transmitter of very important diseases such as malaria or Zika.
Images | Erik Karits
In Xataka | Mosquitoes attack me in summer and I tried these TikTok tricks to get rid of them
GIPHY App Key not set. Please check settings