Close encounters of three kinds: impacts of leg, wing, and body collisions on flight performance in carpenter bees

Abstract

Flying insects often forage among cluttered vegetation that forms a series of obstacles in their flight path. Recent studies have focused on behaviors needed to navigate clutter while avoiding all physical contact, and as a result, we know little about flight behaviors that do involve encounters with obstacles. Here, we challenged carpenter bees (Xylocopa varipuncta) to fly through narrow gaps in an obstacle course to determine the kinds of obstacle encounters they experience, as well as the consequences for flight performance. We observed three kinds of encounters: leg, body, and wing collisions. Wing collisions occurred most frequently (in about 40% of flights, up to 25 times per flight) but these had little effect on flight speed or body orientation. In contrast, body and leg collisions, which each occurred in about 20% of flights (1-2 times per flight), resulted in decreased flight speeds and increased rates of body rotation (yaw). Wing and body collisions, but not leg collisions, were more likely to occur in wind versus still air. Thus, physical encounters with obstacles may be a frequent occurrence for insects flying in some environments, and the immediate effects of these encounters on flight performance depends on the body part involved.

Analysis of collision avoidance in honeybee flight

“…Over the last decade, several modelling studies and reviews have put forth an array of hypotheses on the potential visuomotor control strategy used by insects to deal with spatial clutter [9,10]. However there have been only a few studies [6,11,22,23] that have investigated insect flight behaviour in clutter and evaluated the validity of these hypotheses to elucidate the underpinning control strategy. Lecoeur et al [6] proposed that bumblebees probably regulate lateral control by responding to location in the visual field where the maximum optic flow is experienced; however, frontally occurring obstacles where not considered in their study.…”