Meeting Abstract
Research on animal aerodynamics to date has been largely limited to steady level forward flight. In recent years the techniques used in aerodynamic research have developed and the resolution of the aerodynamic tracks we are able to record and reconstruct has been greatly improved – both temporally and spatially. Therefore, it is now possible to analyse how animals execute manoeuvers through asymmetries in timing and magnitude of forces generated by the two wings dynamically through the wingbeat. In the daily life of any flying animal, manoeuvring is something that is ever present; predators pursuing prey, prey avoiding predator, coping with gusty winds, negotiating cluttered environments, and so on. For bats catching insect prey on the wing, the way they execute their manoeuvers is of direct importance to their biology and ecology. Here we present the results from the first ever study to explicitly explore the aerodynamics of manoeuvring flight in bats. We performed a set of experiments on Brown long-eared bats (Plecotus auritus) flying in a wind tunnel and used time-resolved stereo particle image velocimetry (PIV) to capture the wakes. We encouraged the bats to perform sideways manoeuvers by laterally translating a thin metal sting holding a mealworm at the instant just before the bat approached it. We identified three main phases for analysis; (i) initiation of the manoeuver, (ii) execution of the manoeuver, and (iii) termination of the manoeuver and stabilization and show that, depending on the timing of these events within the wingbeat cycle, the bats can use both upstroke and downstroke to generate the required force asymmetries.
