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Even under the cover of darkness, mosquitoes are surprisingly difficult to swat, and we may be closer to understanding why. They sense and exploit the airflow created by a swatter moving at speed and quickly reorientate themselves so they can ride the air pressure waves to safety.

Little is known about how flying insects anticipate and avoid looming threats in the dark, so and colleagues at Wageningen University in the Netherlands put Anopheles coluzzii mosquitoes to the test. In the lab, the researchers used infrared cameras to track each mosquito as it flew under both twilight and dark conditions. They then used a mechanical swatter to strike at each insect鈥檚 predicted path. The researchers experimented with two disc-shaped swatters 鈥� one solid and one perforated to reduce the air movement generated during a strike.

The team found that, under both twilight and dark conditions, the solid disc was more likely to miss than the perforated disc, suggesting the mosquitoes were sensing and using airflow to avoid getting hit.

When the researchers used high-speed cameras to film the escapes and ran analyses to calculate how the insects were interacting with airflow, they discovered that the mosquitoes make sharp turns away from the swatter as it approaches. Most of the aerodynamic force needed to escape the swatter comes from the mosquito鈥檚 wingbeats. But by reorientating themselves, the insects get as much as 41 per cent of the required escape forces from the air pressure wave generated by the swatter.

鈥淭hey are letting themselves be pushed away by the swatter, but they are also contributing actively to their escape,鈥� says Cribellier. 鈥淎 bit like surfers that swim in the same direction of a wave when they start riding it.鈥�

The mosquitoes may position themselves to catch the wave by sensing small perturbations in the air with their antennae. This wouldn鈥檛 be surprising, says at the Tata Institute of Fundamental Research in India.

鈥淲e have known for a while that the mosquitoes鈥� antennae and their ability to sense mechanical cues is among the keenest of all insects that we know,鈥� he says.

The mosquitoes could also be taking cues from the way their bodies are rolling. Or both of these mechanisms could be working together to help the mosquitoes escape, says at Princeton University.

Cribellier and his colleagues think other smaller flying insects could use similar air-surfing escape tactics.