Floral-Scented Pesticide Lures Mosquitoes to Their Death

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iStock

There are those who argue that mosquitoes serve a purpose, that their droning, blood-gorging presence represents an important link in a fragile food chain. Then there's Agenor Mafra-Neto, who mostly just wants them to die. The chemical ecologist and his colleagues presented their new strategy for mosquito control at the 254th National Meeting & Exposition of the American Chemical Society.

Irritating though they are, mosquitoes are much more than just pests; they're also vectors of deadly diseases that claim millions of lives every year. While some scientists race to develop and administer vaccines against these viruses, others are tackling the problem from the other end, hoping to block the bloodsuckers before they ever pierce a person's skin.

Today's most common chemical mosquito-protection measures are effective, but nonspecific. The same insecticide that takes out a mosquito can kill a bee or poison a dog or a baby. Pesticide runoff can contaminate the water supply. It also can't eliminate all the mosquitoes, and the survivors reproduce, thereby increasing their resistance to the chemicals.

In other words: There's room for improvement. So Mafra-Neto, founder of the pest management laboratory ISCA Technologies, teamed up with researchers from other universities to create something better.

First, they gathered piles of mosquitoes' favorite nectar-producing plants and analyzed the chemical makeup of each flower's fragrance. They exposed mosquitoes to individual elements of each fragrance to find out which ones got their attention, then eliminated any scent that also brought bees to the yard. The final result was an intoxicating perfume of sugars and proteins that no mosquito could refuse.

The researchers mixed this special blend with a highly concentrated, slow-release pesticide called Vectrax, which can be sprayed or spread onto plants and buildings. The pesticide solidifies in teeny droplets and will not spread to other surfaces, but it will spread in the bodies of the mosquitoes who come to taste it.

And taste it they do.

"The blend of chemicals that we use to attract mosquitoes is so powerful that they will ignore natural plant odors and attractants in order to get to our formulation," Mafra-Neto said in a statement. "From a mosquito's point of view, it's like having an irresistible chocolate shop on every corner. The product is so seductive that they will feed on it almost exclusively, even when it contains lethal doses of insecticide."

Mafra-Neto and his colleagues are currently conducting field tests in malaria-vulnerable villages of Tanzania. Their early results suggest that their product can cut mosquito populations by two-thirds in the first two weeks alone, and may be able to eliminate the pests entirely. Mafra-Neto wouldn't be sorry to see them go.

"I truly hate mosquitoes and ticks," he says. "Imagine: Maybe one day we will be able to go into our backyards or parks and not have to worry about being bothered by either of them."

How Did 6 Feet Become the Standard Grave Depth?

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It all started with the plague: The origins of “six feet under” come from a 1665 outbreak in England. As the disease swept the country, the mayor of London literally laid down the law about how to deal with the bodies to avoid further infections. Among his specifications—made in “Orders Conceived and Published by the Lord Mayor and Aldermen of the City of London, Concerning the Infection of the Plague”—was that “all the graves shall be at least six feet deep.”

The law eventually fell out of favor both in England and its colonies. Modern American burial laws vary from state to state, though many states simply require a minimum of 18 inches of soil on top of the casket or burial vault (or two feet of soil if the body is not enclosed in anything). Given an 18-inch dirt buffer and the height of the average casket (which appears to be approximately 30 inches), a grave as shallow as four feet would be fine.

A typical modern burial involves a body pumped full of chemical preservatives sealed inside a sturdy metal casket, which is itself sealed inside a steel or cement burial vault. It’s less of a hospitable environment for microbes than the grave used to be. For untypical burials, though—where the body isn’t embalmed, a vault isn’t used, or the casket is wood instead of metal or is foregone entirely—even these less strict burial standards provide a measure of safety and comfort. Without any protection, and subjected to a few years of soil erosion, the bones of the dearly departed could inconveniently and unexpectedly surface or get too close to the living, scaring people and acting as disease vectors. The minimum depth helps keep the dead down where they belong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article originally appeared in 2012.

One Good Reason Not to Hold in a Fart: It Could Leak Out of Your Mouth

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iStock/grinvalds

The next time you hold in a fart for fear of being heard by polite company, just remember this: It could leak out of your mouth instead of your butt. Writing on The Conversation, University of Newcastle nutrition and dietetics professor Clare Collins explains that pent-up gas can pass through your gut wall and get reabsorbed into your circulation. It's then released when you exhale, whether you like it or not.

“Holding on too long means the build up of intestinal gas will eventually escape via an uncontrollable fart,” Collins writes. In this case, the fart comes out of the wrong end. Talk about potty mouth.

A few brave scientists have investigated the phenomenon of flatulence. In one study, 10 healthy volunteers were fed half a can of baked beans in addition to their regular diets and given a rectal catheter to measure their farts over a 24-hour period. Although it was a small sample, the results were still telling. Men and women let loose the same amount of gas, and the average number of “flatus episodes” (a single fart, or series of farts) during that period was eight. Another study of 10 people found that high-fiber diets led to fewer but bigger farts, and a third study found that gases containing sulphur are the culprit of the world’s stinkiest farts. Two judges were tapped to rate the odor intensity of each toot, and we can only hope that they made it out alive.

Scientific literature also seems to support Collins’s advice to “let it go.” A 2010 paper on “Methane and the gastrointestinal tract” says methane, hydrogen sulfide, and other gases that are produced in the intestinal tract are mostly eliminated from the body via the anus or “expelled from the lungs.” Holding it in can lead to belching, flatulence, bloating, and pain. And in some severe cases, pouches can form along the wall of the colon and get infected, causing diverticulitis.

So go ahead and let it rip, just like nature intended—but maybe try to find an empty room first.

[h/t CBS Philadelphia]

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