How do bees know how far they have flown?
Short answerTrueEmerging research
By watching the world slide past. A bee integrates optic flow — how much the image of the ground moves across her eyes during the flight — rather than tracking time or energy spent. Fly bees to a feeder through a narrow patterned tunnel and they come home and dance a much longer distance than they actually flew.
The tunnel experiment
The demonstration is unusually clean. Bees trained to a feeder reached through a narrow tunnel lined with a busy pattern experience far more image motion than the real distance warrants. They then report a much longer distance in their waggle dances, and recruits following those dances fly out to the wrong place. Changing the pattern to a plain surface, so there is little image motion, produces the opposite error.
Why it works that way
- Energy expended would be a poor measure, because headwinds, load and temperature all change it.
- Elapsed time would be a poor measure for the same reasons.
- Image motion is directly related to ground distance travelled, provided the bee flies at roughly constant height.
Sources
- Honeybee navigation: nature and calibration of the 'odometer' — Science (2000) · Peer-reviewed article
- The Mind of a Bee — Princeton University Press (2022) · Monograph
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