With the arrival of summer, the search for remedies to repel mosquitoes accelerates: air fresheners, citronella candles and bracelets, aerosols, etc. However, no matter how hard we try, many of us cannot avoid being surprised by bites when we wake up or after going outdoors. What if the smell of our personal hygiene products is a determining factor in attracting or repelling mosquitoes? This is the conclusion reached by a group of biochemists from Virginia Tech University.
The researchers report in an article published in the iScience magazine how the application of one or another type of bath gel alters the interactions between mosquitoes and humans. This is because soap —also perfumes or washing machine detergent, to a lesser extent— is capable of modifying our olfactory signature, which makes us more or less attractive to these insects.
Only female mosquitoes feed exclusively on blood after mating. Much of the diet of these insects is made up of the nectar of some flowers and fruits. Mosquitoes are guided by the olfactory signals given off by their hosts, both to locate plants with which to feed themselves and to sources of animal or human blood. The volatile organic compounds contained in bath gels modify our odor footprint, which helps mosquitoes to discriminate between hosts of different species and between individuals of the same species.
The researchers conducted a test to test the relationship between soap application and attractiveness to mosquitoes. To do this, they characterized the odor profiles of four commercial soaps from the Dial, Dove, Native and Simple Truth brands. Using gas chromatography, the biochemists analyzed the attractiveness of the volunteers to Aedes aegypti mosquitoes before and after washing with each of the gels, as well as how attractive the samples of each brand were to them.
The proportions of the chemical substances in gels are decisive in attracting or repelling mosquitoes. That is why, despite the fact that the four brands contained limonene, a repellent substance for mosquitoes, the incidence of other organic components that are naturally involved in the interactions between the mosquito and its host increases the attractiveness for mosquitoes. In other words, the shampoos considered more 'natural' or those in whose composition fruit extracts abound mostly attracted mosquitoes.
On the other hand, the experiment also revealed that, specifically, the coconut aroma is a chemical component with a strong impact in the gel mixtures and that mosquitoes are repulsed by it. Therefore, showering with a coconut-scented gel will help protect you from bites for longer.
