海角大神

To investigate how mosquitoes home in on their targets, biologists from the University of Washington and the California Institute of Technology tracked them tracking us.

The researchers found that mosquitoes rely on a variety of senses to find their meals in a process they divided into stages: first they pick up a scent, then they follow a visual cue, and once they are close enough to the target they sense its body heat.

The scent that alerts mosquitoes to the proximity of a potential target is not that of blood, but of carbon dioxide, the gas we exhale. Mosquitoes can smell the gas from as far as 30 feet away,聽University of Washington researcher and co-author on the paper Jeff Riffell .

鈥淐arbon dioxide is the best signal for a warm-blooded animal, and they can sense that from up to 30 feet away 鈥� quite a distance,鈥� Mr. Riffell said. 鈥淎nd then they start using vision and other body odors to discriminate whether we鈥檙e a dog or a deer or a cow or a human. That may be how they discriminate among potential blood hosts.鈥�

In the study, mosquitoes were put in a wind tunnel that was plain and empty, except for a black dot on the floor to serve as a visual stimulus. The introduction of carbon dioxide into the tunnel triggered the mosquitoes鈥� instinct to search visually for food, Riffel said.

鈥淲hen we gave them the odor stimulus, all of the sudden they were attracted to this black dot,鈥� said Riffell. 鈥淚t鈥檚 almost like the carbon dioxide gas turned on the visual stimulus for the mosquitoes to go to this black dot.鈥�

Adding heat to the dot increased the mosquitoes鈥� attraction to it, Riffel said.

CalTech researcher and first author on the paper Floris Van Breugel that to evade mosquitoes鈥� 鈥渁nnoyingly robust鈥� senses, you would have to 鈥渃apture all the CO2 that you were breathing out,鈥� dress so you were 鈥渧isually camouflaged,鈥� and use another person as a distraction.

"The unfortunate conclusion is that it's very difficult to escape mosquitoes,鈥� he said.