Debris removal by head-pushing in A. florea Fabr. honeybees

The nest of the dwarf honeybee A. florea Fabr. consists of a single comb attached to a tree branch. Recruitment dances take place on the upper surface of the comb that must therefore be kept clear of debris. We report here, for the first time, a behaviour that serves for removing leaves and other foreign objects from the surface of the comb. Individual workers crawl under the object and lift it with their heads, pushing it towards the rim where it eventually slides off the comb. Objects that are heavier or fixed at one end such as leaves are nevertheless lifted and kept away from the surface for up to several minutes. This "head-pushing" is frequently performed without the aid of mandibles, and individuals performing it maintain a distinctive posture, holding the forelegs at an angle without touching the object. Repeated involvement of particular individuals indicate that head-pushers might form a distinct task group.