BEHAVIORAL FEATURES OF A PERIODIC FORM OF MASSED FLIGHT ACTIVITY IN THE GIANT HONEYBEE APIS-DORSATA

A periodic form of massed flight behaviour in Apis dorsata was studied by video recording and image analysis. Two to three times a day the n est turns from the quiescent state into a high level of commotion for about 5 min. The vertical body orientations of the bees in the curtain then become more and more 'disordered'. In one nest, the total percen tage of bees which flew off was less than 20% and the maximum number o f hovering bees at a moment was 2-3% of the bee colony. Half of the cu rtain bees in the surface layer changed their position. The median mov ing index was below 0.3 mm/s in the quiescent condition and it rose up to 1.0 mm/s during massed flight activity. Our observations indicate that this kind of massed flight is quite different from the great defe cation activities reported previously. Although there are diverse form s of massed flight activities in A dorsata, we found that this form of massed flight activity causes the periodical rearrangement of the roo fing layer of curtain. On a Banyan tree we counted more than 100 nests of A dorsata and observed that nests of different areas of the tree d id not supply bees or mass activity simultaneously.