Altitude control in honeybees: joint vision-based learning and guidance

Geoffrey Portelli,Franck Ruffier,Julien R Serres

doi:10.1038/s41598-017-09112-5

Abstract

Studies on insects’ visual guidance systems have shed little light on how learning contributes to insects’ altitude control system. In this study, honeybees were trained to fly along a double-roofed tunnel after entering it near either the ceiling or the floor of the tunnel. The honeybees trained to hug the ceiling therefore encountered a sudden change in the tunnel configuration midways: i.e. a "dorsal ditch". Thus, the trained honeybees met a sudden increase in the distance to the ceiling, corresponding to a sudden strong change in the visual cues available in their dorsal field of view. Honeybees reacted by rising quickly and hugging the new, higher ceiling, keeping a similar forward speed, distance to the ceiling and dorsal optic flow to those observed during the training step; whereas bees trained to follow the floor kept on following the floor regardless of the change in the ceiling height. When trained honeybees entered the tunnel via the other entry (the lower or upper entry) to that used during the training step, they quickly changed their altitude and hugged the surface they had previously learned to follow. These findings clearly show that trained honeybees control their altitude based on visual cues memorized during training. The memorized visual cues generated by the surfaces followed form a complex optic flow pattern: trained honeybees may attempt to match the visual cues they perceive with this memorized optic flow pattern by controlling their altitude.

Highlights

Studies on insects’ visual guidance systems have shed little light on how learning contributes to insects’
The honeybees trained to enter the tunnel near the ceiling changed their flight height when flying below the “dorsal ditch” (Fig. 1Aii)
This 2-step experiment was repeated for twenty-four other individual honeybees trained to enter the tunnel near the floor (Fig. 1Bi) and released via the same entrance under “dorsal ditch” conditions (Fig. 1Bii): the honeybees trained to enter near the floor kept following the floor under the “dorsal ditch” (Fig. 1Bii)

Summary

Introduction

Studies on insects’ visual guidance systems have shed little light on how learning contributes to insects’. When trained honeybees entered the tunnel via the other entry (the lower or upper entry) to that used during the training step, they quickly changed their altitude and hugged the surface they had previously learned to follow. These findings clearly show that trained honeybees control their altitude based on visual cues memorized during training. In the general framework of altitude control, the visual stimuli encountered in a tunnel consist of the optic flow (OF) vector field (its density, magnitude and/or direction) and the retinal positions of any contrasts It has been suggested that the use of an optic flow regulator may explain how flying insects take off, cruise, react to wind, and land at a constant slope on the sole basis of the OF they perceive ventrally[14]

Methods

Results

Conclusion