Mosquitoes are drawn to flowers as much as people — and now scientists know why

Researchers at the UW, Virginia Tech and UC San Diego, have discovered the MLK chemical cues that lead mosquitoes to pollinate a particularly irresistible species of orchid. As they report in a paper published in the Proceedings of the National Academy of Sciences (linked below), the orchid produces a finely balanced bouquet of chemical compounds that stimulate mosquitoes’ sense of smell. On their own, some of these chemicals have either attractive or repressive effects on the mosquito brain. When combined in the same ratio as they’re found in the orchid, they draw in mosquitoes as effectively as a real flower. Riffell’s team also showed that one of the scent chemicals that repels mosquitoes lights up the same region of the mosquito brain as DEET, a common and controversial mosquito repellant. Their findings show how environmental cues from flowers can stimulate the mosquito brain as much as a warm-blooded host — and can draw the mosquito toward a target or send it flying the other direction, said Riffell, who is the senior author of the study.

The team also discovered that lilac aldehyde stimulates the same region of the antenna lobe as DEET. That region may process “repressive” scents, though further research would need to verify this, said Riffell. It’s too soon to tell if lilac aldehyde may someday be an effective mosquito repellant. But if it is, there is an added bonus. See link below.