Radio Script
2000

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Picky Mosquitoes
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INTRO: Although summer is winding down in Alaska, there are still hordes of mosquitoes out looking for an easy meal. As Doug Schneider reports in this week's Arctic Science Journeys Radio, mosquitoes are particular about just whose blood they suck.

STORY: The very thought of mosquitoes make some people start to itch and look about frantically for repellent. But have you've ever wondered just why it is that mosquitoes seem to attack some people more than others? Marta Mueller is a pest control expert with the University of Alaska Cooperative Extension Service. She says mosquitoes have a highly developed sense of smell.

MUELLER: "If you think about it, the mosquito is very tiny. How is it going to find you in this big vast world? They are going to find you by smell. They have chemo-receptors that enable them to detect things like lactic acid from your sweat and carbon dioxide from your breath. So if you're out there working up a sweat and exercising, they're going to find you."

The idea that mosquitoes can sniff out their victims was recently confirmed by research done by Dr. Ulrich Bernier, a research chemist at the U.S. Agricultural Research Service in Gainesville, Florida. But Bernier found something else even more interesting in his research. He discovered that some people seem to smell better than others, at least to mosquitoes.

BERNIER: "We strongly believe that there are some people out there who have a greater tendency to attract mosquitoes than other people. This doesn't mean that it's going to be the same case every day and for every species of mosquito. But what you're going to find is that, in general, some people are going to be more attractive to some species of mosquito and that attraction will generally be the norm for them."

Bernier studies the chemical compounds that are a natural part of human skin, and how those chemicals attract or repel mosquitoes. He says different people have different combinations of these compounds, and that makes some people smell better to mosquitoes.

Still, people who venture into the mosquito's domain do have options. Marta Mueller says there are ways to confuse and discourage the mosquito's keen sense of smell.

MUELLER: "Summer mosquitoes can make enjoying the outdoors absolutely unbearable. One of the things I recommend is to wear a long-sleeved shirt and long pants. Don't go barefoot. You need to wear your socks. There are mosquito shirts, lightweight net shirts with hoods. They'll cover your face and arms and keep the mosquitoes from getting in and biting you. If you are out for a half hour or so, say walking your dog, it's okay to use something like Skin So Soft. This provides an oily barrier on your skin that the mosquitoes won't bite through. But Skin So Soft does not work as a repellent. It works as a barrier to keep the mosquitoes from biting you. So they will find you. You will probably smell just as good to them. Chemicals that serve as repellent such as DEET or some of the botanical repellents, like citronella—these actually serve to confuse the mosquito's sense of smell."

OUTRO: Our thanks to Earthwatch Radio at the University of Wisconsin Sea Grant Institute for help on this week's story. This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider.

For more information about mosquitoes, visit these web pages:

Interview with Ulrich Bernier; "Science News" articles in April 2000 edition.

"Science News"

Earthwatch Radio

Alaska Cooperative Extension Service

Thanks to the following individuals for help preparing this script:

Marta Mueller, Integrated Pest Management Technician
University of Alaska Fairbanks
Alaska Cooperative Extension Service
Fairbanks, Alaska 99775-8155
Phone: 907-474-2428
Email: ftmrm@uaf.edu

Ulrich R. Bernier, research chemist
USDA Agricultural Research Service
Center for Medical, Agricultural, and Veterinary Entomology
1600 SW 23rd Drive
Gainesville, FL 32608

Richard Hoops, Producer
Earthwatch Radio
Sea Grant Institute and the Institute for Environmental Studies
University of Wisconsin-Madison
1975 Willow Drive
Madison, WI 53706-1177
Phone: 608-263-3149
Email: rhoops@seagrant.wisc.edu