Re: Why are some people more attractive to mosquitoes than others?

Hi Daniel,

One of the hardest jobs some parasites have is finding a suitable host. While some parasites are lucky enough to be able to wait for their hosts to come to them, others, such as blood-feeding flies, must seek their meals out.

Before it's even time to choose a particular host, a mosquito has to get itself to an area where its hosts live. Mosquitos can use the presence of light at night to zero in on a house or camp fire. As it gets closer, the mosquito needs to begin figuring out which objects they should try biting. The carbon dioxide we breathe out and the heat of our bodies attract mosquitos even closer. People who breathe out more carbon dioxide and/or produce more heat will attract more mosquitos to the area.

Once it's made it that far, a mosquito has to choose whether or not to try to feed. Different species of mosquito prefer different species of animals to feed from. So the mosquito tests the air for tiny scents given off by its favorite animal with the mosquito's sensitive antennae. Some of these scents come from the host's skin secretions. If the mosquito is lucky enough to have several good hosts to choose from, it may choose the host with the most perfect combination of these scents.

So the members of your family that are "mosquito bait" probably have scents that match more perfectly with what the mosquitos are looking for than other members of your family. Let's look at what makes people secrete different scents.

Many people don't realize that the skin is, in fact, an excretory organ. A large amount of your body's waste products is excreted out through sweat glands. Variations in the waste products present in your sweat depend a lot upon what you eat. Vegetarians smell differently from people who eat meat. Drinking alcohol or taking other drugs also changes what you smell like. So differences in diet change how mosquitos evaluate you as a possible meal. But genetics also factor into what your skin secretions contain. Your metabolism is strongly influenced by your genes, and it is your metabolism that produces the bulk of the waste chemicals released through your skin. Metabolic wastes, such as lactic acid, attract mosquitos.

Another factor you might not have considered is the genetics of the mosquitos in your area. It's possible that if your family moved to another area, the mosquitos there might have different ideas of which of you make the most perfect host.

For more information on the amazing life cycle of mosquitos, plus information on how to control mosquitos, check out this site.

For great mosquito trivia, check out this site.

Thanks for your question!

Your friendly MAD Scientist,

John