Theories abound as to why certain individuals are more prone to mosquito bites while others remain unaffected. In a recent study, titled "Soap Application Alters Mosquito-Host Interactions" published in the journal iScience, a team of researchers from Virginia Tech found that using certain soaps could either attract or repel mosquitoes.
These results, however, differed amongst individuals due to interactions between the soaps used and each person's distinct olfactory profile. Neuroethologist Clément Vinauger, the senior author of the study, said in a news release via EurekAlert! that it is remarkable how an individual who is highly appealing to mosquitoes when unwashed can become even more attractive to them with one soap and repellent or repulsive with another soap.
Chemicals in Soaps Attract or Repel Mosquitoes
The impact of added scents on mosquito attraction has received less attention compared to studies on chemicals present in a person's body odor that mosquitoes find appealing.
While female mosquitoes are known for feeding on animal blood, they also consume nectar like their male counterparts. This led researchers to explore whether the scents commonly found in soaps could alter mosquito feeding habits.
Vinauger explained in an email to Gizmodo that many soaps are fragranced with chemicals associated with pleasant floral and plant scents. As mosquitoes also use plant-emitted volatiles to locate sources of nectar, it was hypothesized that incorporating these chemicals into human body odor might affect mosquito attraction. However, experimental testing was required to validate this theory.
The research team enlisted four human volunteers and began by identifying the distinct odor signatures of each person. The volunteers were then instructed to wash with four different soap brands: Dial, Dove, Native, and Simple Truth.
Female Aedes aegypti mosquitoes, known carriers of diseases, were exposed to fabric samples worn by the volunteers before and after washing. The results demonstrated noticeable variations in mosquito preferences following the use of different soaps, although the effects differed among the brands and individuals.
Vinauger emphasized the significant impact of soap application on body odor, particularly in terms of incorporating plant-emitted chemicals into the scent. Furthermore, the study revealed the importance of the interaction between specific soap chemicals and an individual's body odor in determining their attractiveness to mosquitoes after using soap.
Interestingly, some volunteers experienced increased mosquito attraction after washing with Dove and Simple Truth soaps, while the Native brand soap consistently repelled the insects.
The researchers also identified potential chemicals in these soaps that appeared to be responsible for attracting or repelling mosquitoes. Notably, a coconut-scented chemical exhibited the most effective repellent properties against mosquitoes.
New Research Adds Information for Making Better Mosquito Repellants
The research has expanded the understanding of mosquito attraction, while also raising new questions and potential directions for future studies. According to Medical News Today, one intriguing finding is that despite containing limonene, a known mosquito repellent, three out of the four tested soaps increased mosquito attraction.
This suggests that the relative amounts of chemicals in mixtures, rather than the absolute quantities, are crucial in determining mosquito behavior. The researchers now aim to investigate how these chemical interactions are processed in the mosquito's brain.
While this study provides a proof of concept regarding the interaction between soaps and body odor, further funding is being sought to expand the number of volunteers and soaps in the study. This will enable a deeper understanding of the underlying chemical processes involved. Ultimately, the findings have the potential to contribute to the development of improved mosquito repellents in the future.
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