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Mosquito Magnets | Earth Wise

November 30, 2022 By EarthWise Leave a Comment

Some people are mosquito magnets

We’ve all probably had the experience of being in the great outdoors with other people and having some of them being nearly devoured by mosquitoes while others didn’t get bitten at all.  It seemed like some people are mosquito magnets while others just aren’t the insects’ cup of tea, so to speak.

There have been various theories proposed over the years including such things as it being a question of blood type, or it having to do with how close one’s blood vessels are to their skin surface.

A new study by the Howard Hughes Medical Institute and the Rockefeller University has uncovered what appears to be the real explanation.  According to the paper published in the journal Cell, certain body odors are the deciding factor.  Every person has a unique scent profile associated with different chemicals present on their skin.  The researchers found that people whose skin produces high levels of carboxylic acids are the most attractive to mosquitos.

The researchers collected scent samples from participants by having them wear silk stockings on their arms for six hours.  The nylons were then cut into pieces and the pieces exposed to mosquitos.  After several months of head-to-head battles between various nylon samples, the study clearly demonstrated that the samples from subjects with higher levels of carboxylic acids in the skin were far more attractive to mosquitos.

Humans produce the substance at much higher levels than other animals.  There is little one can do about their own levels.  Changing one’s diet or what soap they use doesn’t seem to make a difference. 

Perhaps researchers can come up with some method of breaking down carboxylic acids in the skin in the future.  Until such time, there are really people who are mosquito magnets.

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Some People Really Are Mosquito Magnets, and They’re Stuck That Way

Photo, posted September 4, 2014, courtesy of James Gathany / Centers for Disease Control via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Harnessing The Smell Of Fear | Earth Wise

September 28, 2021 By EarthWise Leave a Comment

Harnessing the smell of fear to drive away pests

Plant-eating insects present a major problem for farmers and home gardeners.  Aphids, for example, are a highly destructive pest to many crops.  Their large numbers and ability to transmit plant pathogens make them a persistent problem for growers.

Pesticides are chemical substances that are commonly used to prevent, destroy, repel or mitigate pests.  They include insecticides for insects, rodenticides for rodents, herbicides for weeds, and fungicides for microorganisms.  According to the U.S. Geological Survey, approximately one billion pounds of these chemicals are used in the United States every year.     

But pesticides can also contaminate soil, water, and other vegetation, as well as kill many non-target species.  Exposure to these chemicals is dangerous for human health. 

According to a new study, researchers from Pennsylvania State University have developed a way to bottle the “smell of fear” produced by predators in order to repel and disrupt pests naturally without the need for these harsh substances.  The researchers recently presented their findings at the American Chemical Society meeting.  

Aphids happen to be a favorite food of ladybugs. Aphids and other herbivorous insects will steer clear of fields and gardens if they smell predators nearby.  The researchers identified and extracted the volatile odor profile from ladybugs.  The researchers used the compounds to create a special odor blend that can be used in an essential oil diffuser to spread the scent across a garden or field. 

The research team plans to conduct field tests to see if the effects outside are similar to what was observed in the lab.  A natural and effective pest repellent would be a big win for people and the planet.  

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Web Links

Protecting gardens and crops from insects using the ‘smell of fear’

Protecting gardens and crops from insects using the ‘smell of fear’ (YouTube)

Photo, posted May 10, 2011, courtesy of DM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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