HEAD AND ABDOMINAL POSTURE AND THE ORIENTATION OF HONEYBEES ON VERTICAL COMBS

Honeybee foragers returning to the hive from a rich source of nectar o ften perform a ''dance'' on the vertical surface of the comb. The dire ction of one component of the dance relative to gravity can be correla ted with the direction relative to the sun that a recruited bee would have to take from the hive to reach the nectar. For the directional in formation contained in the dance to be useful in guiding the recruited bee, both dancer and recruit must have precise information about the direction of gravity. In this study we took flash photographs of undis turbed bees on the surface of comb while they were carrying out their normal activities. Measurements of the angular displacement of the hea d and abdomen in relation to the thorax showed that the abdominal, but not the head, displacement was often correlated with the direction of gravity. The exception was seen in bees oriented horizontally on comb , when many brought both heads and abdomens into line with the thorax. The morphology of the neck organs, the mechanics of the articulation between the head and thorax, and the central projections of receptors suggest a role for the neck organs in the control of the head position , perhaps during flight. The morphology of the petiolar organs and the central projection of the ventral petiolar organs confirms their role as monitors of lateral abdominal excursions.