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News ID: 46941
Publish Date : 28 November 2017 - 21:46

Rough Lessons Can Lessen Pull of Human Scent on Mosquitoes




DENVER (Science) - After unpleasant lessons in the lab, mosquitoes can learn some restraint in their zest for pursuing the scent of human skin.

The test, a kind of aversion therapy for mosquitoes to see if they can associate smells with bad experiences, was reported at the annual Entomological Society of America meeting.

"Mosquitoes have this very challenging task of finding food that’s hidden under the skin of mobile and defensive hosts,” said Clément Vinauger of Virginia Tech in Blacksburg. He’s investigating whether repeated scares such as near misses of a slapping hand might change mosquito reactions to odors.

Female mosquitoes go about their dangerous blood quest by tracking a mix of cues: plumes of carbon dioxide, the sight of looming objects, up-close body heat and body scent (SN: 8/22/15, p. 15). The final targeting can be annoyingly picky. Even within the same target species, such as humans, some individuals turn out to be mosquito magnets, while others aren’t so alluring.

Vinauger and colleagues wafted odors over Aedes aegypti mosquitoes during 10 rounds of 30-second educational shaking in a small cage. Outside the lab, slapping at a mosquito may not seem to discourage the relentless return of the whining, but the test setup found an effect.

A day after stern lessons, the mosquitoes had become "indifferent” to the skin odor of normally quite attractive humans, Vinauger reported November 7 at the meeting. When placed at the base of a Y-shaped tube, mosquitoes flew into the Y branch that smelled of human skin no more than would be expected by random chance.