Meeting Abstract
Although the elongated morphology of mosquito larvae shares similarities with several other aquatic organisms, many of which swim under comparable hydrodynamic conditions using undulatory gaits, their locomotion consists of unsteady sideways strokes of the paddle-like end of their articulated body. This pulls back a large volume payload (the insect thorax) located at the other end of their body. We hypothesize that such a gait may help transport larger payloads at certain hydrodynamic regimes, as compared to undulatory swimming gaits. We analyzed the kinematics of larvae motion using videos, to break down their gait into different instances of thrust generation. Previous studies explain the drag-based thrust generated solely by the paddle motion. However, these studies overlook other important inertial thrust contributions. We identified translations of the center of mass due to changes of the body configuration across the stroke time, as well as body rotations due to angular momentum conservation, that enhance the paddling action by conveniently reorienting the body at each stroke. To this end, we created a model that faithfully captures the kinematics of the larvae gait in a form of a large amplitude, small wavelength traveling wave along the body, giving us the possibility to track the center of mass motion using different body segment mass properties. This opens questions about the role of discrete articulated segments present on the larvae’s body, compared to the continuous body in undulatory swimmers, the role of a passive/active paddle in comparison to tail fins, and how the payload payload impacts the gait’s cost of transport to favour unsteady gaits over undulatory ones. To make such comparisons, we complemented our model with a physical robot to experimentally test and validate our observations on living larvae.
