Bumblebees display characteristics of active vision during robust obstacle avoidance flight

Abstract

Insects are remarkable flyers and capable of navigating through highly cluttered environments. We tracked the head and thorax of bumblebees freely flying in a tunnel containing vertically oriented obstacles to uncover the sensorimotor strategies used for obstacle detection and collision avoidance. Bumblebees presented all the characteristics of active vision during flight by stabilizing their head relative to the external environment and maintained close alignment between their gaze and flightpath. Head stabilization increased motion contrast of nearby features against the background to enable obstacle detection. As bees approached obstacles, they appeared to modulate avoidance responses based on the relative retinal expansion velocity (RREV) of obstacles and their maximum evasion acceleration was linearly related to RREVmax. Finally, bees prevented collisions through rapid roll manoeuvres implemented by their thorax. Overall, the combination of visuo-motor strategies of bumblebees highlights elegant solutions developed by insects for visually guided flight through cluttered environments.

Through Hawks’ Eyes: Synthetically Reconstructing the Visual Field of a Bird in Flight

“…Again this was not observed in the counterfactual gaze strategy that we considered, in which the virtual camera’s principal axis was aligned with the bird’s head velocity. This is in accordance with similar findings in lovebirds (Kress et al, 2015 ), bees (Ravi et al, 2022 ) and humans (Raudies et al, 2012 ; Rothkopf & Ballard, 2009 ), all of which seem to fixate on the edges of objects that can be perceived as obstacles, and on the centre of objects perceived as goals. Moreover, in the flight corresponding to the second leg of the trial, the bird seemed to align its visual field first with the edge of the landing perch and then with its centre before landing (see Online Resources 12 and 13, around frames 2029 and 2184 as numbered in the video).…”

“…2 ). Although analogous data have been generated for insects, these were produced at much lower spatial resolution (Ravi et al, 2022 , 2019 ; Schulte et al, 2019 ; Stuerzl et al, 2016 ; Stürzl et al, 2015 ). Additionally, none of these previous works involved a unique method to produce the full set of outputs we consider here.…”

“…It can also be done via software, using rendering methods (Holmgren et al, 2021 ). Rendering is particularly attractive because it offers complete control of the detail presented over the visual field (Holmgren et al, 2021 ; Neumann, 2002 ), and it is well suited to scientific inference because of the possibility of defining alternative views (Eckmeier et al, 2013 ; Ravi et al, 2022 ; Miñano & Taylor, 2021 ; Bian et al, 2021 ). For example, in a series of works studying the effectiveness of movement-based signalling in lizards, renderings were used to investigate the effect of different lighting and wind conditions (Bian et al, 2018 , 2019 , 2021 ).…”

“…1 a), and panoramic images of the ants’ habitat (Zeil et al, 2014 ). The role of optic flow in bee flight has been analysed using a basic geometric reconstruction of the laboratory environment (Ravi et al, 2019 , 2022 ), whereas the homing flight of bees and wasps has been studied using detailed 3D models of their natural environment (Stürzl et al, 2015 ; Stuerzl et al, 2016 ; Schulte et al, 2019 ). The latter used models obtained using laser scanners, structure-from-motion (SfM), and photographic reconstruction techniques.…”

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

“…Many birds, for instance, nest and perch in trees and pursue prey through dense foliage [1,2], and many insects forage for nectar and pollen among dense patches of flowers [3,4]. In each case, animals navigate around a series of vegetative structures that functionally serve as obstacles and constrain navigable paths [5,6]. Traversing obstacles while in flight requires coordinated detection of obstacles (e.g., visually) and rapid alteration of the flight path, for example by decelerating, accelerating, or changing body orientation [7][8][9][10][11].…”