Meeting Abstract
Many species of flying animals carry loads when airborne. Mosquitoes can fly with a blood load equal to or higher than their unfed body mass. We studied how carrying blood loads affects the take-off performance of female malaria mosquitoes, the fitness of which depends on their ability to escape from a host after blood feeding. We used stereoscopic high-speed videography data of female Anopheles coluzii during takeoff to measure their 3D wing and leg motions. Comparing unfed with blood-fed mosquitoes allowed us to assess how takeoff performance was affected by a blood load, and to determine how they changed their kinematics when carrying this load. During the non-aerial phase of takeoff (prior to lift-off, when their feet leave the substratum), mosquitoes straighten their legs and beat their wings. The duration of the non-aerial phase was longer for bloodfed animals than for unfed ones, and their bodies were oriented more vertically when they carried a blood load in the abdomen. At the moment of lift-off, the velocity of bloodfed mosquitoes was 20% lower, and their ascent angle was 26% lower than those of unfed ones. Once airborne, bloodfed females flew along more horizontal paths than did unfed ones (average trajectory angle of the aerial phase was 57% lower), such that bloodfed females flew at heights that were 33% lower than those of unfed ones. Female A. coluzii also responded to carrying blood loads by increasing their wing stroke amplitude, but not by changing wingbeat frequency. Thus, once airborne, the flight speeds of blood-carrying animals were the same as for those without loads. These results demonstrate partial kinematic compensation for increased loads but also reduced speeds and angles of takeoff, possibly influencing escape success from the host.
