Fruity floral notes of purple passion fruit, peony and vanilla orchid. For once we’re not talking about wine, but perfume. More specifically, Victoria’s Secret Bombshell. While this sickly-sweet combination may prove intoxicating to some people, it seems to be a buzzkill for mosquitoes.
Examining the repellent properties of various commercially available products, scientists found that this perfume exerted strong effects that lasted more than two hours. That came as a bit of a surprise, because previous studies have shown that mosquitoes are attracted to floral scents, thus recommendations have been made to avoid drowning yourself in such fragrances to avoid the hungry, disease-ridden mouths of these insects.
While interesting, the main endeavor of the study was not actually to find out which perfumes make mosquitoes start voraciously licking their chops or flee in the opposite direction. Scientists wanted to compare the effectiveness of various DEET-containing versus DEET-free repellants, specifically on two species of mosquito that are significant transmitters of human disease: the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopticus). These can carry a whole host of nasties, including the pathogens responsible for dengue fever, chikungunya, and of course, yellow fever.
We already know that DEET is an extremely effective insect repellent; it was invented during World War II, so we have had plenty of time to scrutinize its actions. Despite its widespread use and consideration as a very safe repellent to humans, though, there have been fears over its side effects, although these seem to be largely unfounded and possibly worsened by our general dislike of “chemicals.”
Nonetheless, various alternatives have surfaced over the years, and given the global burden of mosquito-borne diseases, it’s imperative we know which ones do what they say on the tin. Sure, no repellent can guarantee you won’t get bitten, but effective products can significantly reduce the chances of contracting diseases like malaria.
For their investigation, published in the Journal of Insect Science, researchers from New Mexico State University tested three DEET-containing and four DEET-free repellents, all of which are commercially available. The natural alternatives contained commonly used substances like geraniol, oil of lemon eucalyptus, and citronella. They also used a supposed mosquito-repelling bath oil, floral perfume and vitamin B patch, the latter of which has been available as a repellent for decades. Supposedly, the patch changes our blood chemistry and smell, making the consumer less attractive to mosquitoes.
The team then applied the various products to volunteers and used a fan to blow their scent through a tube towards the mosquitoes, which were kept inside a container. If the insects tried to move towards the scent, they were said to be attracted, whereas not moving or flying in the opposite direction were signs they were repelled.
As expected, they found the DEET-containing products strongly repelled both species, exerting effects over prolonged periods of time. One of the natural repellents, containing oil of lemon eucalyptus, was found to be as good at repelling as these, but its effects weren’t as long-lasting. The other DEET-free products generated a mixed bag of effects, however, with two producing little to no repellency. In addition, the skin patch did nothing to repel the insects.
But it was perhaps the floral perfume that produced the most surprising result, given the fact that published literature suggests these fragrances may attract mosquitoes. The researchers suggest it probably masks our own scent, but caution that they used high concentrations of the stuff, so don’t start swapping proven repellents for Chanel’s Coco any time soon.