Meeting Abstract
On roughened surfaces, such as those equivalent to the roughness of skin, male and female Aedes aegypti mosquitoes employ a takeoff strategy similar to those witnessed in other Diptera; they initiate their takeoff with a push from mid- and hind-legs. Such a twitch of the legs lasting 15 ms allows tarsi to remain static until the legs reach maximum extent and are drawn inward as the body rises at 0.25 m/s when legs leave the ground under flapping. In contrast, polished surfaces provide little traction to the mosquito pushing with its legs, inducing tarsal slip and decreasing the efficacy of the push. Instead, the vast majority of mosquitoes prefer initiating takeoff from polished surface with a leg strike, in which one or both hind-legs are raised into the air before swinging downward like a golfer’s swing and striking the ground at 0.55 m/s. The ensuing reaction force lifts the mosquitoes body skyward at more than 0.5 m/s when legs leave the ground and full flapping commences. We hypothesize mosquitoes select the particular strategy which imparts greater performance by way of maximum stability or efficiency during the first critical wingbeats of flight. We characterize the takeoff kinematics of mosquitoes launching unprovoked from polished and roughened horizontal surfaces using high-speed videography, and rationalize the shift in their takeoff strategy through kinetic considerations.
