sunset from behind the wire

sunset from behind the wire

Monday, August 12, 2013

It Bites

Scientists file it in the Goldilocks Principle folder. While this usually explains the zone that Earth occupies (not too hot, not too cold) where life can exist, it's also applied to animals and humans, who can survive and reproduce only if the temperature is just right. Too hot and they will overheat. Too cold and they will freeze.

To stay in their comfort zone, animals have evolved very sensitive temperature sensors to detect the relatively narrow margin in which they can survive. Until recently, scientists knew very little about how these sensors operated.

Have you ever wondered why mosquitoes seem to hoan in on one person and tend to leave the person standing next to them alone (for the most part)? Yes, there may be perfumes, personal odor based on diet and other variables, but the relative body heat that a person puts out needs to be factored into the preference matrix. THE LITTLE BASTARDS ARE USING Infra Red ON US. 

A team of Brandeis University** scientists has discovered a previously unknown molecular temperature sensor in fruit flies belonging to a protein family responsible for sensing tastes and smells. These types of sensors are present in disease-spreading insects like mosquitoes and tsetse flies and may help scientists better understand how insects target warm-blooded prey -- like humans -- and spread disease.

The discovery is published in today's advance online edition of the journal Nature.

Biting insects, such as mosquitoes, are attracted to carbon dioxide and heat. Notice how mosquitoes always seem to bite where there is the most blood? That is because those areas are the warmest, says Paul Garrity, a professor of biology in the National Center for Behavioral Genomics at Brandeis who co-authored the paper.

"If you can find a mosquito's temperature receptor, you can potentially produce a more effective repellent or trap," Garrity says. "The discovery of this new temperature receptor in the fruit fly gives scientists an idea of where to look for similar receptors in the mosquito and in other insects."

The newly discovered sensor belongs to a family of proteins, called gustatory receptors, that have been studied for over a decade but never linked to thermosensation, Garrity says. In previous studies, other gustatory receptors have been found to allow insects to smell carbon dioxide and to taste sugar and bitter chemicals like caffeine.

But in fruit flies, one type of gustatory receptor senses heat rather than smell or taste. This receptor, known as Gr28b, is responsible for sensing external temperatures and triggering a quick response if temperatures exceed the fly's Goldilocks zone, Garrity and his team discovered.

The research also reconciles previously conflicting views of how a fruit fly senses warmth, by showing that the insect has distinct external and internal systems for thermal detection.

** "The temperature tastes just right: Scientists discover previously unknown thermal sensor in insects linked to taste, smell."ScienceDaily, 7 Aug. 2013. Web. 9 Aug. 2013.


10 comments:

  1. Replies
    1. I like honey bees, because they pollenate and make honey.

      I like lady bugs because they get good press and are in at least half of all children's books.

      And I like the preying mantis - professional courtesy.

      Delete
  2. I have never found a mosquito in my Starbucks iced frappuccino.

    ReplyDelete
  3. And they come after beer drinkers too... :-)

    ReplyDelete
    Replies
    1. How could they be so cunning? Draw blood and get a "buzz" on as well?

      Delete
  4. Do not wear perfume that smells of carbon dioxide.... so that's where I've been going wrong.

    ReplyDelete
    Replies
    1. Sweet smells attract them -- and you breathe out CO2. Heat also attracts them. It would seem that: (1) eating garlic (2) stop breathing all together (3) reducing your body temperature to that of a frozen, beverage (containing no caffein) and (4) shooting your body into outer space -- taken together, may save you from a mosquito bite.

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  5. If you hold your breath, and don't expel the CO2, you combat the effects global warming AND insects won't detect you...until you exhale, which we apparently have to do.

    We must be careful, it is now coming out that it was in fact pesticides (improper use of them, I say) that lead to worldwide honey bee deaths (http://en.wikipedia.org/wiki/Bee_deaths).

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    Replies
    1. Nobody said that you have to exhale. In fact, if everyone stopped breathing NOW, it might end global warming...or at the very least, our concern with global warming...

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