Manipulating the light/dark cycle: effects on dopamine levels in optic lobes of the honey bee (Apis mellifera) brain.

This study examines the relationship between cyclical variations in optic-lobe dopamine levels and the circadian behavioural rhythmicity exhibited by forager bees. Our results show that changing the light-dark regimen to which bees are exposed has a significant impact not only on forager behaviour, but also on the levels of dopamine that can be detected in the optic lobes of the brain. Consistent with earlier reports, we show that foraging behaviour exhibits properties characteristic of a circadian rhythm.