[Colony defence of Asian honey bees]

Colony Defence in Asian Honey Bees. 1. In Ais cerana, Apis dorsata and Apis florea a defence behaviour (Körperschütteln) can be released by the approach of flying insects. Films of Apis cerana colonies exhibiting this behaviour were made and anaylysed. 2. Körperschütteln "could not be released by various mechanical and chemical" stimuli. Only the movement of a dark object before light background was effective in releasing this behaviour. 3. The optimal angular velocity of the dark object when moved on a moving disk was between 80 degrees to 250 degrees per sec. The optimal size for stimulation was between 5 degrees and 12 degrees (visual angle). 4. The stimulatory effect was not greatly influenced by the shape of the dark object. 5. Continued stimulation over a 90 min period resulted in 80% reduction in the number of responding bees. 6. The colony's ability to discriminate between returning forager bees and other flying insects is discussed.