Meeting Abstract
Historically, the analyses of flight control and maneuvering have focused largely on aerodynamic forces generated by wings. Yet body (airframe) deformations may also be important and are often associated with maneuverability and flight control. Examples of non-wing maneuvering behaviors include changes in leg posturing as well as abdominal flexion. Abdominal flexion in particular may contribute to maneuverability because the abdomen comprises a large proportion of the weight of an insect. Thus, both active and passive changes in abdominal position physically redirect the inertia of the animal. Recent multi-body dynamics models also suggest abdominal motions during flight may contribute to maneuverability. If indeed such motions are critical, restriction of abdominal movement would yield poorer flight performance. To test this hypothesis, we glued a carbon fiber rod between the thorax and abdomen, thereby restricting abdominal flexion during flight for hawkmoths (Manduca sexta). The moths were tasked with feeding from a 3-D printed flower in natural light and temperature conditions. Without any modifications, 45 of 89 animals flew successfully and approached the flower. Only 5 of 38 trials across 29 moths flew successfully and approached the test flower. We also developed a sham treatment with the same weight of carbon fiber but severed into two pieces—one piece glued to the thorax, and the other glued to the abdomen allowing abdominal flexion. Of these sham experiments, 8 of 16 trials across 12 moths. These results suggest that abdominal flexion is necessary for flight control in hawkmoths. Our results also suggest multiple actuators are critical for flight control in insects.
