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This article comes from the official account of Wechat: SF Chinese (ID:kexuejiaodian), author: SF

The researchers built an experimental site the size of an ice rink in Zambia to study how mosquitoes choose their prey. Understanding mosquito bites can help scientists design better traps and insect repellents.

By Liu Jiayu / tr. by Phil Newell)

Mosquitoes are one of the deadliest animals in the world. They kill 700000 people a year by spreading diseases such as dengue and yellow fever. Anopheles gambiae is an important malaria vector in sub-Saharan Africa, killing more than 600000 people each year.

Body odor, carbon dioxide and body temperature all remind mosquitoes of prey. Through the olfactory neurons on the antennae, they can capture the smell from 60 meters away.

Most researchers have studied insect preferences in a relatively small, restricted laboratory environment, which makes it impossible to determine how different odors attract mosquitoes over long distances. and how mosquitoes make decisions among competing odors.

Mosquito preference test is actually a good thing for mosquitoes to smell bad. But what attracts mosquitoes? Recently, scientists have built an outdoor rink the size of a skating rink in Zambia to understand how mosquitoes locate their prey dozens of meters away. The study found that the body odor of prey plays a key role.

Alicia Showering, of the London School of Hygiene and Tropical Medicine, said: "this finding may help develop more effective mosquito control strategies to better prevent mosquito-borne diseases."

The study is one of the first to test how Anopheles gambiae, an important malaria vector in Africa, can remotely locate a human host in a "real" environment (a 1000-square-meter arena).

Researchers from the Malaria Institute of the Bloomberg School of Public Health at Johns Hopkins University and the Macha Trust compared the release of carbon dioxide from body temperature, odor and respiration as bait in mosquito hunting.

The test site is equipped with landing pads heated to human skin temperature (35 ℃). The researchers released 200 hungry mosquitoes into the test site every night and monitored them with infrared cameras. When mosquitoes land on the mat, they are ready to bite their prey.

The researchers monitored the test site for seven days, during which six people slept in single tents around the arena, with a pipeline leading from their tents to the test site. The researchers used modified air-conditioning pipes to pump air from each tent, along with body odor from sleep volunteers, to a landing mat at the test site.

Mosquitoes have a clear preference for body odor the researchers found that the body odor composition of a lucky volunteer was completely different from that of others, and he had not been "favored" by mosquitoes for seven days.

Most mosquitoes seem to prefer people who smell a mixture of carboxylic acids, an oily secretion that moisturizes and protects our skin.

The team found 40 different mixtures of the same chemicals in the body odors of six people. Differences in mixtures may be affected by factors such as diet, skin secretions, microbes and exhalation.

"We don't know which aspects of skin secretions, microbial metabolites or expiratory emissions really drive this, but we hope we can figure it out in the next few years," said Stephanie Lankie-Tulner, a postdoctoral fellow at the Bloomberg School of Public Health at Johns Hopkins University.

The team also compared body odor bait with carbon dioxide bait and found that mosquitoes had a clear preference for body odor.

After studying mosquito bites, "we can isolate and study the volatile compounds in body odors that are more attractive to mosquitoes," Shaw said. "better and more attractive mosquito traps can be developed by synthesizing these odors. to reduce mosquito bites and prevent the spread of disease.

References:

Https://www.science.org/content/article/world-s-largest-scent-arena-reveals-bloody-preferences-mosquitoes

Https://www.sciencefocus.com/the-human-body/always-bugged-by-mosquitos-blame-your-body-odour/

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