Escaping blood-fed malaria mosquitoes minimize tactile detection without compromising on take-off speed

To escape after taking a blood meal, a mosquito must exert forces sufficiently high to take off when carrying a load roughly equal to its body weight, while simultaneously avoiding detection by minimizing tactile signals exerted on the host's skin. We studied this trade-off between escape speed and stealth in malaria mosquitoes, Anopheles coluzzii, using 3D motion analysis of high-speed stereoscopic videos of mosquito take-offs and aerodynamic modelling. We found that during the push-off phase, mosquitoes enhanced take-off speed by using aerodynamic forces generated by the beating wings in addition to leg-based push-off forces, whereby wing forces contributed 61% to the total push-off force. Exchanging leg-derived push-off forces for wing-derived aerodynamic forces allows the animal to reduce peak force production on the host's skin. By slowly extending their long legs throughout the push-off, mosquitoes spread push-off forces over a longer time window than insects with short legs, ther...