Mechanisms of dance orientation in the Asian honey beeApis florea L.

Summary

Early studies of dance communication inApis florea had shown that waggle dances are not performed on a vertical plane and oriented to gravity, as in the other species ofApis, but instead take place on the flattened top of the exposed comb and are oriented to celestial cues directly. More recent experiments showed thatA. florea can dance in the absence of a view of the sun or blue sky, but did not establish what mechanism permitted this orientation. I now report that dances can be oriented directly to landmarks visible from the nest, the first evidence of an environmental feature other than celestial cues or gravity being involved in dance orientation. Landmarks near the nest are probably used to refer to celestial cues, in a fashion analogous to the use of broad features of the landscape by honeybees in order to learn the sun's course, which permits them to determine their flight angle on overcast days or at night, and to compensate accurately for solar movement.Apis florea may therefore be able to learn the sun's course with respect to two sets of landmarks.

In other experiments I have examined the influence of slope onA. florea's dance orientation to visual references. In the first extensive observations of its dances on a vertical plane, I have amply confirmed that this species cannot transpose light and gravity in setting its dance angle, as the other species ofApis can. Nor do dancers orient so as to match visual information seen during the dance with that remembered from the flight. Patterns in the data when the same patch of sky was presented from different angles suggest instead thatA. florea continues to orient to projections of celestial cues onto the horizontal plane even when dancing on a steep slope. This compensation for slope may involve an ability to detect gravity and factor it out in aligning the dance to celestial cues.

These insights suggest thatA. florea's dance orientation system has been adapted to requirements imposed by its nesting behavior, and has diverged sharply from the system shared by the other species ofApis.