Blood-sucking mosquitoes keep their cool

Dec 15, 2011
The mosquito performs evaporative cooling. The retention of the fluid drop attached to the abdomen end leads to a fall of the abdomen temperature causing a clear temperature gradient along the mosquito body. N.B., the color of the droplet does not reflect the real temperature, because of the difference in the emissivity between the cuticle of the mosquito and the drop surface. Credit: Lahondčre et al. Current Biology

No one likes being bitten by whining mosquitoes, but have you ever considered what the experience is like for them as their cold-blooded bodies fill with our warm blood? Now researchers reporting online on December 15 in Current Biology have uncovered the mosquitoes' secret to avoiding heat stress: they give up cooling droplets of their hard-won meals.

The study shows for the first time that blood-feeding insects are capable of controlling their body temperature, the researchers say.

"During feeding on a warm-blooded host, such as a human being, mosquitoes ingest quite a large amount of hot blood in a short period of time," said Claudio Lazzari of Université François Rabelais. "We aimed to determine to what extent these insects are exposed to the risk of overheating during the blood intake."

Mosquitoes have to be quick, lest their host turns into a potential predator, Lazzari points out. But that influx of heat could send their internal body temperature soaring past physiological limits.

Insects' generally do depend on the environment around them. However, earlier studies have shown that insects, including bees and aphids, can control their temperature with beads of nectar or sap. Mosquitoes, too, will give up drops of fluid during feeding.

"What intrigued us was why they eliminate fresh blood, which is a precious and risky-to-obtain nutritive element," Lazzari said.

To find out, he and Chloé Lahondère used a camera that depends on heat to form images, much as a regular camera depends on light. Those images highlighted differences in temperature between the body parts of mosquitoes as they fed. Their heads reached temperatures close to that of the ingested blood, while the rest of their bodies remained closer to ambient temperature. That temperature variation wasn't observed when mosquitoes dined on sugar water instead.

The researchers showed that the cooling depended on those drops of fluid the insects excrete from their backsides as they feed. Lazzari and Lahondère say that the mosquitoes' strategy no doubt protects them and any malaria-causing (Plasmodium) parasites they might be carrying. The new understanding of mosquito physiology is more than a curiosity; it could lead to strategies aimed to control mosquitoes and the diseases they spread.

"Blocking or delaying the production of the excreted fluid would have a double impact on the physiology of : on water and thermal balance," Lazzari said. "Indirectly, this would affect microorganisms transmitted by by modifying the thermal environment to which they are exposed."

Explore further: Discovery in the fight against antibiotic-resistant bacteria

More information: DOI:10.1016/j.cub.2011.11.029

add to favorites email to friend print save as pdf

Related Stories

Mosquitoes supply spider with blood

Oct 11, 2005

Scientists in Sydney, Australia, say they've determined an East African species of jumping spider prefers to prey on blood-engorged female mosquitoes. And that, the Macquarie University researchers said, demonstrates a rare ...

Scientists Build Anti-Mosquito Laser

Mar 16, 2009

(PhysOrg.com) -- In an effort to prevent the spread of malaria, scientists have built a laser that shoots and kills mosquitoes. Malaria, which is caused by a parasite and transmitted by mosquitoes, kills about ...

Entomologists seek fungus to blunt mosquitoes' sense of smell

May 07, 2009

Sick people often lose their sense of smell and their appetite. If this happened to mosquitoes, they would not be able to feed on humans and spread malaria. A team of Penn State entomologists is looking for an insect disease ...

Recommended for you

Discovery in the fight against antibiotic-resistant bacteria

50 minutes ago

For four years, researchers at Universite catholique de Louvain have been trying to find out how bacteria can withstand antibiotics, so as to be able to attack them more effectively. These researchers now understand how one ...

Stem cells born out of indecision

50 minutes ago

Scientists at the University of Copenhagen have gained new insight into embryonic stem cells and how blocking their ability to make choices explains why they stay as stem cells in culture. The results have just been published ...

Protection of the mouse gut by mucus depends on microbes

3 hours ago

The quality of the colon mucus in mice depends on the composition of gut microbiota, reports a Swedish-Norwegian team of researchers from the University of Gothenburg and the Norwegian University of Life Sciences in Oslo. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.