Fatal Attraction: Why Do Mosquitoes Favor Some People Over Others?

April 14th, 2016

By Gary Evans, Senior Staff Writer

Why are mosquitoes attracted to certain people over others? Why can't we simply eradicate the pests? Such questions are being raised as the summer of mosquito-borne Zika virus looms in the U.S.

We sought the counsel of the American Mosquito Control Association (AMCA) on such issues, particularly after reading that those with type O blood, beer consumption, foot odor and heavy breathing may be seen by a female mosquito as dream date in a Tinder ad. Interestingly, the blood taken by the pest is not a food source for the female adults but a way of providing iron for mosquito offspring.

“Why some people seem to be more attractive than others to mosquitoes is the subject of much repellent -- and attractant for traps -- research being conducted nationwide,” the AMCA states. “Carbon dioxide is the most universally recognized mosquito attractant and draws mosquitoes from up to 35 meters. When female mosquitoes sense carbon dioxide they usually adopt a zigzagging flight path within the plume to locate its source. Once in the general vicinity of a potential host, other cues predominate, including body odors (sweat, lactic acid, etc.) and heat. Odors produced by skin microflora also play a part in inducing the mosquito to land. … People drinking beer have been shown to be more attractive to mosquitoes. Limburger cheese has also been found to be attractive. Scientists have theorized that this may explain the attraction some mosquitoes find for human feet.”

On a serious note, Zika virus poses a significant threat to pregnant women and their unborn children. Unfortunately pregnant women seem to be among the groups favored by mosquitoes. Research with mosquito-borne malaria and other studies suggest pregnant women may have a rise in body temperature and exhale more carbon monoxide than they do normally. Both factors can attract mosquitoes so it will be absolutely critical for pregnant women to follow public health advice to prevent mosquito bites that could threaten the fetus.

Concerning myths and urban legends, the AMCA says eating bananas does not attract mosquitoes, but wearing perfume does. On the other hand eating garlic and taking vitamin B12 have been proven in controlled laboratory studies to have no impact on mosquito biting. Please alert your garlic-eating friends at the next cookout. A 2004 study found that human blood group O subjects generally attracted more Aedes albopictus mosquitoes than other blood groups (B, AB, and A). However, statistical significance was only established for mosquito preference for 0 over type A.

Mosquitoes have been in North America since the Cretaceous period 100 million years ago when Tyrannosaurus Rex walked the earth. Thus the premise of the bug preserved in amber in Jurassic Park. It’s hard to imagine mosquitoes penetrating dinosaur skin but they have been currently known to take the blood of reptiles and snakes.

It is thought that smallpox is the only living organism that man has had the opportunity to willfully eradicate from the planet. However, for various political and scientific reasons the trigger remains unpulled and frozen vials of the disfiguring scourge remain in the U.S. and Russia. The AMCA is understandably being asked why we can’t target mosquitoes for complete eradication, give the various diseases they have spread over the years.

Here is their answer: “Mosquitoes fill a variety of niches which nature provides. As such, placing a value on their existence is generally inappropriate. ... Their adaptability has made them extraordinarily successful, with upwards of 2,700 species worldwide. Mosquitoes serve as food sources for a variety of organisms but are not crucial to any predator species. … Given that Nature abhors a vacuum, other species will fill the niches vacated by the mosquitoes after an initial shuffling period of variable length. Be advised, though, that species replacing mosquitoes may be even worse - it's extremely difficult to predict. Mosquitoes' ability to adapt to changing environments would make them all but impossible to eradicate.”