Neural control of circadian rhythms and social behavior: involvement of circadian clock and aminergic neurons.

Time-related behaviors are controlled by the output from clock neurons with aminergic neurons. In this review, I summarize the circadian clock system and time-related behaviors with potential effects due to monoamines in social insects. In social bees, the circadian clock system is built into some behaviors, including the navigation system based on the sun compass, time-related mating flights, and time-place learning. The sun compass incorporates the circadian changes in sky polarization patterns and solar azimuth, allowing bees to obtain a stable directional signal throughout the day. Time-related mating flights involve synchronizing sexual activity between males and gynes at a time of day. Time-place learning requires time memory based on the internal clock and associating the site of a food source with the time of day when flowers frequently secrete nectar. The neural circuits involved in these behaviors may interact with the clock and aminergic neurons in particular brain areas.