Mosquito myths

It has been particularly hot, wet, and rainy in many parts of the country so far this summer–perfect mosquito weather. Of course, you don’t have to worry about that, if you’re one of the “lucky” ones who don’t attract mosquitoes. But is this really a medical fact? Are some people “immune” to mosquitoes and some “mosquito magnets”?

I’ll answer all those questions in a moment. But first, let’s back up.

First of all, why are mosquito bites so irritating?

Mosquitos feed on blood. So when they “bite” you, they actually inject a “stinger” or feeder tube called a proboscis into your skin. Through the proboscis, the mosquito releases a small amount of anti-coagulant called hirudine. This anti-coagulant acts like heparin to thin your blood so it won’t clog in the proboscis. But your immune system recognizes hirudine as a foreign substance. So you get an immune reaction: redness, swelling, heat, itchiness, and even pain.

This is also how mosquitoes can act as carriers of infectious diseases like yellow fever and malaria. And newer diseases like West Nile virus and St. Louis encephalitis virus. The virus or parasite multiplies in the mosquito. Then, the mosquito injects the virus into your blood with the hirudine, when it “bites” you.

So, now back to my big question…

Do mosquitoes really “bite” some people more often than others?

Jerry Butler, Ph.D. is a professor emeritus at the University of Florida, where they should know a little something about the subject. In a recent interview, he said, “One in 10 people are highly attractive to mosquitoes.” According to another estimate, one in five people have this distinct honor.

Common lore says that mosquitos prefer blondes. But hair color seems to have no basis in fact. Other theories say that mosquitoes like you more if you have “sweet blood” or wear perfume. But here again, these theories don’t stick with the science.

Here is what we do know as scientific fact: Male mosquitoes don’t feed on human blood at all. And the females appear to select their victims using a very clear set of criteria.

First of all, there’s your size. Mosquitos find you because you exhale carbon dioxide and two other chemicals called acetone and estradiol. Naturally, larger people produce more carbon dioxide and more of these chemicals.

In addition, your skin harbors bacteria that produce still more attractive chemicals.

So, here again, larger people have more skin surface and produce more of these chemicals on their skin. This explains why mosquitoes tend to bite adults more often than children. And they are more likely to seek out men rather than women.

Also, it explains why mosquitoes always seem to end up crashing your backyard parties…whether you invite them or not. And it’s not because they like your barbeque. Rather, larger groups of people produce bigger chemical clouds and lots of carbon dioxide.

Mosquitoes also seek out people who produce lactic acid. This acid builds up in your muscles during heavy exercise. And when you exercise, you also breathe more rapidly. This causes more carbon dioxide to build around you. That’s why mosquitoes heartily attack you when you go for a run outside. Interestingly, some cosmetic creams also contain lactic acid. So maybe you should take a look at your beauty cream, if you’re a frequent mosquito target.

The third substance we know mosquitoes like is cholesterol. Or, to be more precise, mosquitoes like cholesterol’s metabolic byproducts that accumulate in your skin.

People who metabolize cholesterol quickly reduce levels in their blood. And they send the byproducts to their skin. These byproducts attract the mosquitoes. Just don’t expect a cholesterol-lowering statin drug to prevent mosquito attacks.
You can find lots of chemical-based mosquito repellants on the market. But avoid toxicity to yourself and the environment by trying a natural, plant-based repellent. Plants don’t attract mosquitoes. They don’t have blood. And they consume, rather than produce, carbon dioxide. They also naturally make chemicals that repel insect predators.

Eucalyptus oil and citronella oil are two of the most powerful natural mosquito repellants. And they work well when rubbed onto your skin.

You can make your own homemade mosquito repellant with either of these natural plant oils. Just combine 10 to 25 drops of either plant oil with two tablespoons of olive oil. (Other cooking oils will work too, such as sunflower oil. I just don’t recommend actually cooking with them!) Then rub the mixture onto your skin.

You can also burn citronella candles when spending time outside in the summer. But these candles also produce some carbon dioxide, which may be why they rarely keep you completely bite-free.


1. “Ask Healthy Living: Do Mosquitoes ‘Like’ Some People More Than Others?” Huffington Post (, 6/4/13