Thursday, February 23, 2012

The Curious Case of Mosquitoes

Life really sucks if you're a mosquito. Apart from the ability to master flight, there's no good in being a parasite--your dinner can turn around and smack you dead if you're not fast enough, and your food can cause your little body to overheat. 

Oh yeah, and some neighbors will hunt you down and suck the blood right out from your belly.

According to a study in the journal Current Biology, Chloé Lahondère and Claudio R. Lazzari found out that these little vampires excrete and hang on to a single bead of blood to reduce the heating effect via evaporation.

High temperatures can have deleterious effects on insects' physiology. But some insects are dependent on warm-blooded host. And since they do not sweat like us, there must be some kind of cooling strategy to keep them from dying.

The scientists conducted a real-time infrared thermographic analysis of mosquitoes' body temperature during feeding on both warm blood and sugar solution. They found that anopheline mosquitoes can decrease their body temperature during blood feeding thanks to evaporative cooling of fluid droplets, which are excreted and maintained at the end of the abdomen. The mosquitoes that excrete a drop of blood have lower body temperatures than those that don't.
But life isn't just about keeping cool at the dining table. Engorged mosquitoes have to be wary of their hungry neighbors too, because they will attempt to steal your food, right out from your belly.
A technician from the Department of Entomology, University of Georgia reported that she saw a mosquito taking blood from another engorged one.

So the scientists prepared two groups of Aedes mosquitoes; one group allowed to dine on a chicken, while another starved. Right after the feeding, the starved ones were put together with the engorged mosquitoes, which remained motionless. The scientists reported that the starved individuals were attracted to the engorged mosquitoes and attempted to feed. Some eventually succeeded in taking blood from their burdened neighbors.
Aedes aegypti feeding on an engorged Aedes aegypti. Image: "Mosquitoes Feeding On Engorged Moquitoes", A. Burns Weathersby, Hyong-Sun Ah, John W. McCall.
I ain't sure about you, but I prefer to stay human.
Forget about flying.


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