Mosquito Bytes

 

1. Mosquito alert
2. Whining in your ear
3. Malaria
4. Illnesses expand (Dengue)
5. Death to mosquitoes
6. Climate change=more disease?
7. Advice for the weary (repellent pictured)
8.Stop already! (Q & A)

 

Swat twice for good luck
Biodidac, © Houseman: closeup of mosquitoes labella looks like a mouth from a horror movie with tiny, numerous "teeth" looking elements inside the sparsely haired 'mouth' When it comes to maligning mosquitoes, almost any place is a good place to start. How 'bout a slap-happy guide to a misguided menace?

"The better to eat you with my dear!" This amazingly detailed and somewhat gruesome image is a microscopic photo of a mosquito's mouthparts. This is the tip of the labella, and those 'lips' are it's labellar lobes. Photo by Antoine Morin Jon Houseman, (c) BIODIDAC.

What are mosquitoes?

Why do they have such an attitude?

And how can we control their wretched habit of biting people and spreading disease?

Van Nostrand's Scientific Encyclopedia describes mosquitoes quite simply: "A small two-winged fly with slender body, long legs, and narrow wings bearing scales along the veins."

Sounds innocuous, right? Not a word about the mosquito's mouth, which is designed to furtively slip through your flesh. Nothing about the itching you feel as your body tries to decompose and eliminate chemicals the mosquito injected during the bite. Not a word about the grave diseases you could catch from mosquito: West Nile, encephalitis, yellow fever, dengue, malaria, etc.

Not a word about the clever anti-coagulants the whiner makes so your blood will flow freely into its gut.

Not a mention of the need that females (of many mosquito species) have to suck blood so they can reproduce.

Blood -- supplied by an unwilling coyote, a cow, or a three-year-old playing in the backyard -- supplies protein for the skeeter's eggs. (This should not sound strange -- after all, you probably eat eggs to get protein. Mosquitoes just have it backwards, that's all.)

Mosquito stands on the water, an egg "raft" is being produced behind her.
A female Culex species of mosquito is shown here laying her eggs. The Culex lay their eggs in this "raft" formation. Photo courtesy of CDC.

Too bad mosquito eggs hatch...
A mosquito deposits its eggs in some standing water. The eggs turn into larvae, which eat by filtering water. In warm weather, mosquitoes can produce a new generation in just seven days, although two weeks is a more common span.

Adults lay eggs, which become larvae, pupae, and then enter the adult, to lay more eggs. Adapted from original image--courtesy Parkland Services of Edmonton. (c) City of Edmonton

Most fly less than a mile during their lifetimes, but the ferocious salt-marsh mosquito, found in the Everglades and other coastal locations, can migrate 75 to 100 miles, according to Don Barnard, research leader at the Agricultural Research Service's Mosquito and Fly Research Unit.

Contrary to popular misconception, mosquitoes are good for something -- specifically, feeding swallows, purple martins, bats, and some predatory insects.

That means they do good by dying?
Yes.

This sounds better and better.

The mosquito's need for standing water to lay eggs has not prevented them from ranging from sea level to altitudes as high as 10,800 feet (3,600 meters). Nor has it prevented humorists from many states, including Wisconsin, home of The Why Files, from proclaiming them the state bird.

Despite an occasional case of malaria in non-tropical locations like Michigan and New York City, and the spread of West Nile virus across parts of the United States, most people in temperate climates view mosquitoes as a nuisance.

Is it just my imagination, or do mosquitoes really bite me more than you?
The mosquito's mouth is designed to slip through your flesh It's not your imagination. Some people are unusually attractive to the bloodsuckers, says Barnard. Put two potential victims in a room, and one may get 10 bites, and another 50 -- or even 100.

Why? That's not clear, but his research group is looking into the role played by the 300-odd chemicals produced by the skin. How do they know skin chemicals attract skeeters? By simply wiping a piece of glass on the skin and allowing mosquitoes to "visit" the glass, Barnard says. Consistently, plates from different people attract different numbers of skeeters.

In a search for better skeeter attractants, Barnard's group is sorting through those chemicals to see which ones, and which combinations, are most attractive to this most unattractive animal.

Why would they want to ATTRACT skeeters? To find substances that will help monitor skeeter populations.

You can run, but you can't hide
Aside from skin chemicals, mosquitoes have other ways of finding you: they can detect both carbon dioxide and lactic acid (produced by muscle metabolism) in your breath. They can also detect infra-red light from your body.

Let's scratch beneath the surface of mosquito science and examine the battle against the resurgent killer malaria.

 

 

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