Bumblebees compensate for the adverse effects of sidewind during visually guided landings

Abstract

Flying animals often encounter winds during visually-guided landings. However, how winds affect their flight control strategy during landing is unknown. Here, we investigated how sidewind affects the landing performance and sensorimotor control of foraging bumblebees (Bombus terrestris). We trained bumblebees to forage in a wind tunnel, and used high-speed stereoscopic videography to record 19,421 landing maneuvers in six sidewind speeds (0 to 3.4 m s−1), which correspond to winds encountered in nature. Bumblebees landed less often in higher windspeeds, but the landings durations from free flight were not increased by wind. By testing how bumblebees adjusted their landing control to compensate for adverse effects of sidewind on landing, we showed that the landing strategy in sidewind resembled that in still air, but with important adaptations. Bumblebees landing in a sidewind tended to drift downwind, which they controlled for by performing more hover maneuvers. Surprisingly, the increased hover prevalence did not increase the duration of free-flight landing maneuvers, as these bumblebees flew faster towards the landing platform outside the hover phases. Hence, by alternating these two flight modes along their flight path, free-flying bumblebees negated the adverse effects of high windspeeds on landing duration. Using control theory, we hypothesize that bumblebees achieve this by integrating a combination of direct aerodynamic feedback and a wind-mediated mechanosensory feedback control, with their vision-based sensorimotor control loop. The revealed landing strategy may be commonly used by insects landing in windy conditions, and may inspire the development of landing control strategies onboard autonomously flying robots.

Measuring the Flight Trajectory of a Free-Flying Moth on the Basis of Noise-Reduced 3D Point Cloud Time Series Data

“…Additionally, it can be used to study a wide range of flying species by enhancing and broadening the measurement system. For instance, a study that examined the influence of sidewind on bumblebee flight trajectories utilized a relatively small flight arena (48 × 48 cm) and verified that bumblebees could land accurately on the target even under the presence of sidewind [ 35 ]. It would also be possible to investigate the flight trajectories of a target species over larger areas and/or under low-light conditions using the methods proposed in this study.…”