How do mosquitoes always get away? UC Berkeley researchers uncover secret to stealthy takeoffs

Cherry Wu/Staff

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Scientists at UC Berkeley and Wageningen University in the Netherlands have discovered the secret to mosquitoes’ stealthy takeoffs.

The researchers arrived at their conclusion by analyzing mosquitoes’ flight biomechanics, according to Sofia Chang, a researcher on the project and UC Berkeley graduate student. Previous research conducted at the Dickinson Lab at Caltech determined that the legs of flies contain a unique musculature. According to Chang, this musculature is not present in mosquitoes.

Mosquitoes use a quarter of the force that flies do when taking off, Chang said.

“Mosquitoes must be good at escaping,” Chang said. “How are they able to escape from us?”

Bart Biemans, Wageningen University researcher and co-author of the study, focused on examining the musculature in the legs of mosquitoes. Their combined research, Chang said, showed that the mosquito’s relatively small leg force and strong wings allow for its covert takeoffs. A mosquito is able to make these stealthy takeoffs with an empty belly or one filled with a blood meal, which nearly doubles its weight, according to a campus press release.

The research team, Chang said, was curious about how mosquitoes are able to fly with their heavy body mass.

Because of the high speed at which mosquitoes move their wings, Chang and her team put the insects under a camera that records 125,000 frames per second in order to visualize the wingbeats in a single cycle. Chang initially fed the insects blood from her own arm before Wageningen University entomologist Jeroen Spitzen provided the researchers with equipment to feed them artificially, the press release stated.

Hundreds of mosquitoes were filmed, and 63 videos were analyzed in the study: 32 of blood-filled mosquitoes and 31 of unfed mosquitoes.

The team developed a model to examine how much lift mosquitoes produce with each wingbeat, according to Chang. The researchers found that mosquitoes have a “shallow” wing amplitude, less than half that of a bee, Chang said.

Although smaller wing amplitudes typically imply smaller force, Chang said, the rotational drag and trailing edge vortex in mosquito wings generate a higher force. Trailing edge vortex allows the wing to flip direction and causes more rotation and lift in a given amount of time.

Despite the success of the team’s efforts, Chang said scientists “still do not know much about mosquito flight. Period.”

According to Chang, there is a dearth of flight biomechanics research in mosquitoes. She said she would like to pursue more work in this field, adding that she also wants to learn more about how blood intake affects mosquitoes.

“I want to understand how the diversity of mosquito blood-feeding affected their evolution,” Chang said.

Contact Rishabh Nijhawan at [email protected] and follow him on Twitter at @realRishNij.