The role of optic flow pooling in insect flight control in cluttered environments

Julien Lecoeur,Marie Dacke,Emily Baird,Dario Floreano

doi:10.1038/s41598-019-44187-2

Julien Lecoeur, Marie Dacke + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-44187-2

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Abstract

Flight through cluttered environments, such as forests, poses great challenges for animals and machines alike because even small changes in flight path may lead to collisions with nearby obstacles. When flying along narrow corridors, insects use the magnitude of visual motion experienced in each eye to control their position, height, and speed but it is unclear how this strategy would work when the environment contains nearby obstacles against a distant background. To minimise the risk of collisions, we would expect animals to rely on the visual motion generated by only the nearby obstacles but is this the case? To answer this, we combine behavioural experiments with numerical simulations and provide the first evidence that bumblebees extract the maximum rate of image motion in the frontal visual field to steer away from obstacles. Our findings also suggest that bumblebees use different optic flow calculations to control lateral position, speed, and height.

Highlights

By rapidly processing visual information into motor commands, insects are able to navigate safely in cluttered environments with a level of miniaturisation and refinement that is unmatched by man-made systems
Flying insects control their flight speed using optic flow– the magnitude of translational optic flow in the lateral, ventral or dorsal visual field12–14–which is maintained at a set-point such that, in experimental corridors, flight speed decreases with the distance between the walls15–18
We investigate the effect of clutter on flight control in bumblebees and use mathematical models to understand how and where optic flow is being measured for this

Summary

Introduction

By rapidly processing visual information into motor commands, insects are able to navigate safely in cluttered environments with a level of miniaturisation and refinement that is unmatched by man-made systems. Flying insects control their flight speed using optic flow– the magnitude of translational optic flow in the lateral, ventral or dorsal visual field12–14–which is maintained at a set-point such that, in experimental corridors, flight speed decreases with the distance between the walls. Flying insects control their flight speed using optic flow– the magnitude of translational optic flow in the lateral, ventral or dorsal visual field12–14–which is maintained at a set-point such that, in experimental corridors, flight speed decreases with the distance between the walls15–18 It appears that flight speed is regulated by optic flow in the lateral, ventral and dorsal visual fields. Previous work provides little insight into how insects measure optic flow for flight control because the pattern of optic flow generated in the experimental corridors that are typically used in these studies is qualitatively independent of viewing angle and the nearest obstacles (the walls) occur only in the lateral visual field

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