Can bees see polarised light?
Short answerTrueEstablished evidence
Yes, and it is how they navigate under cloud. Sunlight scattered by the atmosphere is polarised in a pattern radiating around the sun's position, and a specialised region at the top of each compound eye is built to read it. A bee that can see one patch of blue sky can work out where the sun is.
How it works
The dorsal rim of the compound eye contains receptors arranged with their light-absorbing structures aligned, which makes their response depend on the orientation of the light's polarisation. Because the sky's polarisation pattern is fixed relative to the sun, reading a patch of it gives a solar bearing without the sun being visible.
What it is for
The sun compass. A foraging bee holds her course relative to the sun's bearing, and a dancing bee encodes a direction relative to it. Without a way to find the sun under cloud, both would fail on most days in a temperate climate. It also has to be corrected for time, because the sun moves while the bee is inside the nest, and bees do correct for it.
Sources
- The Dance Language and Orientation of Bees — Harvard University Press (1967) · Monograph
- The Mind of a Bee — Princeton University Press (2022) · Monograph
How sources are selected and weighted is set out in the sources and evidence policy.