Hate mosquitoes? Avoid beer!

Creative Commons/Chris CottermanScientists have identified several factors that appear to play a role in making certain individuals more tasty to mosquitoes, including your choice of drinking beverage (avoid beer.)
Thanks primarily to a very wet spring, Minnesota’s mosquito populations have climbed to levels that are triple the 10-year average for this time of year.

So you could be forgiven for thinking the little buggers are targeting you specifically each time you step outside.

Or … maybe they are seeking you out. For as science writer Joseph Stromberg points out in a recent online article for the Smithsonian, an estimated 20 percent of us “are especially delicious for mosquitoes” and, thus, are more likely to get bitten.

Scientists have identified several factors that appear to play a role in making certain individuals more tasty to mosquitoes, writes Stromberg. Some you can’t control, such as blood type, genetics, skin bacteria and metabolism. But others you can, such as the color of your clothes (neutrals are best) and your choice of drinking beverage (avoid beer.)

Here are Stromberg’s explanations of a few of these factors:

• Blood type. Not surprisingly — since, after all, mosquitoes bite us to harvest proteins from our blood — research shows that they find certain blood types more appetizing than others. One study found that in a controlled setting, mosquitoes landed on people with Type O blood nearly twice as often as those with Type A. People with Type B blood fell somewhere in the middle of this itchy spectrum. Additionally, based on other genes, about 85 percent of people secrete a chemical signal through their skin that indicates which blood type they have, while 15 percent do not, and mosquitoes are also more attracted to secretors than nonsecretors regardless of which type they are.

• Skin bacteria. Other research has suggested that the particular types and volume of bacteria that naturally live on human skin affect our attractiveness to mosquitoes. In a 2011 study, scientists found that having large amounts of a few types of bacteria made skin more appealing to mosquitoes. Surprisingly, though, having lots of bacteria but spread among a greater diversity of different species of bacteria seemed to make skin less attractive. This also might be why mosquitoes are especially prone to biting our ankles and feet — they naturally have more robust bacteria colonies.

• Beer. Just a single 12-ounce bottle of beer can make you more attractive to the insects, one study found. But even though researchers had suspected this was because drinking increases the amount of ethanol excreted in sweat, or because it increases body temperature, neither of these factors were found to correlate with mosquito landings, making their affinity for drinkers something of a mystery.

You can read Stromberg’s article in full on the Smithsonian website.

Low-tech deterrent

And while we’re on the subject of mosquitoes, the New York Times ran a short piece earlier this week on a low-tech mosquito deterrent: the electric fan. Apparently, mosquitoes are slow, weak fliers (average speed: about 1 to 1.5 miles per hour) and therefore will avoid the wind from the fan.

But that may not be the only reason fans help keep mosquitoes away. The wind from the fan also disperses the carbon dioxide exhaled by nearby humans. And, as Stromberg points out in his Smithsonian article, mosquitoes use carbon dioxide emanations to locate their targets. Amazingly, they can detect carbon dioxide from distances of 164 feet.

Prevention is important

Of course, avoiding itchy welts isn’t the only reason you should protect yourself from mosquito bites. Some species are vectors for the transmission of serious and even life-threatening diseases, including, here in Minnesota, the West Nile virus and La Crosse encephalitis.

To prevent mosquito bites and to keep the insects from multiplying, health officials recommend that you do the following:

• Avoid outdoor activity at peak mosquito-feeding times (dawn and dusk).
• When you are outside, wear long-sleeve shirts and long pants.
• Use a mosquito repellant containing up to 30 percent DEET (10 percent for children). Spray the repellant on your clothes, not on your skin.
• Make sure you get rid of water-holding containers (including buckets and tires) from your property. If you have a birdbath in your garden, remove and replace its water at least once a week.

And, perhaps, do your beer drinking indoors.