I Didn’t Know That

Q: Why do mosquitoes bite some people more than others?

A: No one is really certain, according to entomologist Thomas W. Scott, director of the UC Davis Mosquito Research Laboratory. But the question is important because mosquitoes carry human diseases. A person who is bitten more frequently is thus at a higher risk of infection.

The problem is that mosquitoes use a variety of cues that vary depending on whether they are far from the host (color, contour and movement, for example) or near (temperature, humidity, carbon dioxide and lactic acid). Because mosquitoes can switch from one cue to another very quickly, Scott said, it has been virtually impossible so far to determine experimentally exactly which characteristic makes one person more appealing than another.