Is Your Bug Spray Actually Attracting Mosquitoes?

You Should Know: Mosquitoes may be evolving to associate DEET, the active ingredient in most insect repellent sprays, with food. That’s right: Your bug spray might actually attract, not repel, mosquitos. 

Going Deeper: DEET is considered the gold standard of mosquito repellents. It works by disrupting mosquitoes’ ability to detect us, while also creating an odor and taste they generally find unpleasant. But a new lab study suggests mosquitoes may be able to learn around DEET. Researchers trained Aedes aegypti mosquitoes by pairing the smell of DEET with warm blood. After repeated exposures, many of the insects began associating DEET with food and were attracted to it rather than repelled by it — essentially a mosquito version of Pavlov’s dogs. 

Takeaway: It’s possible that mosquitoes could start perceiving DEET as a reward, which raises concerns for those spending time outdoors. However, experts stress that these were laboratory conditions and DEET is still an effective repellent. One doctor says these results are “unlikely to occur in nature.”

Bottom Line: You can keep using DEET, but the study suggests that reapplication may be more important than previously thought.