There are two kinds of people at summer cookouts: those who are getting “eaten alive” by mosquitoes, and those who haven’t noticed a single bite.
So why can some people enjoy their burgers in bliss while others unceasingly swat at exposed skin? According to a new study of twins, genetics partially explains how attractive we are to mosquito bites.
You Look Tasty
Over the years, scientists have shown that mosquitoes prefer some humans to others. Pregnant women, for example, are more attractive to mosquitoes than non-pregnant women. People who weigh more also tend to be favored targets.
Previous studies have also shown that body odor influences our attractiveness to mosquitoes. Building upon this insight, scientists wanted to see if there might be an underlying genetic component that makes some people smell tastier to mosquitoes than others.
Offering a Hand
Scientists recruited 18 identical and 19 non-identical female twin pairs that were willing to offer their blood as a snack. For each trial, scientists sent a group of 20 female Aedes aegypti mosquitoes into a Y-shaped tube, which forced the insects to make a decision and fly toward their preferred smell. A different batch of mosquitoes was used in each trial.
As it turned out, identical twins were equally attractive to mosquitoes, but non-identical twins were not. In fact the trait was highly heritable: an estimated 83 percent of the variability in bite likelihood was due to genetics. That makes mosquito attractiveness equally heritable as height or I.Q., for instance.
Although it was just a pilot study, the results indicate genetic controls of our body odor play some role in our attractiveness to mosquitoes. Scientists published their results Wednesday in PLOS One.
Further research will have to delve into what exactly is causing the difference between identical and non-identical twins — whether repellant chemicals from some people or attractive chemicals from others. Scientists say they will continue to investigate the genetically controlled mechanisms that dictate these signals.
Their work could someday yield better insect repellants, and that’s a big deal. Apart from annoying, itchy bites, mosquitoes carry nasty disease like dengue fever and malaria.
Any method to keep these pests far, far away is a win for humanity.
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