Why Garlic Repels Mosquitoes and Keeps Them From Breeding
The garlic was considered a natural mosquito repellent for centuries. In popular culture, it is believed that its pungent odor repels these insects which, in addition to causing sleepless nights, transmit diseases such as dengue or malaria. However, this belief has a scientific explanation.
A group of scientists from Yale University conducted a phytochemical analysis of 43 fruits and vegetables to identify natural compounds capable of interfering with the reproductive behavior of flying insect pests. To do this, the team used fruit flies, a species that often mates for food, as a model organism.
From this behavior, researchers hypothesized that certain fruits and vegetables could contain substances capable of altering the reproductive processes of these insects. After exposing different specimens to the pureed food included in the experiment, they observed that none of the products had a significant aphrodisiac effect. However, they found that garlic completely blocked mating and egg-laying.
After this initial discovery, researchers sought to determine the source of the effect and focused their attention on the influence of garlic on the flies’ senses of taste and smell. To do this, they carried out two experiments. In the first, they arranged the garlic puree so that the insects could only smell it; in the second, they allowed them to taste it too. The results showed that taste was the factor that actually inhibited reproductive behaviors.
The team then performed a chemical analysis of the garlic to identify the compound responsible for this effect. They determined that diallyl disulfide was the element causing the inhibition. In practice, this substance acts on a sensory receptor present in the fly’s taste organs, called TrpA1.
The TrpA1 receptor functions as a sensor that triggers immediate rejection responses when it detects potentially harmful tastes. According to an article published in the journal Cell, garlic specifically activates a group of bitter taste-sensitive neurons containing this receptor. This activation not only causes a physical avoidance response but also changes at the molecular level by modifying the expression of different genes.
Among the alterations identified, that of a gene closely linked to the sensation of satiety stands out, suggesting that contact with garlic compounds directly interferes with the biological processes that regulate the appetite and feeding of these insects. The authors posit that increased satiety appears to lead to behaviors that limit mating and reproduction, primarily in females.
A natural repellent for many species
In addition to fruit flies, the experiments were replicated on other flying insects, including two species of mosquitoes that transmit diseases such as yellow fever, dengue fever and the Zika virus, as well as tsetse flies. In any case, tests have shown that garlic can act as an effective remedy to discourage breeding.
The researchers’ results suggest that this plant, Allium sativum, could be used as a tool to combat various insects harmful to human health and agriculture.
“It’s inexpensive and grown all over the world,” said John Carlson, a Yale professor and co-author of the study. “The idea of using it to ward off blood-sucking creatures was proposed in 1897 by Bram Stoker in his novel Draculaand maybe he was right.
This story was originally published on WIRED en Español and was translated from Spanish.
