Figure 3. Additional moistening of pollen provisions.

Schematic rendering of four video stills (from Video S2) depicting the addition of a regurgitated droplet of sugar-water to the pollen provision carried on the corbiculae while hovering. a) Placement of both front basitarsi at the base of the outstretched proboscis. Basitarsi are thereafter pulled downward to the tip of the proboscis in one swiping movement. b) Appearance of a droplet at the tip of the proboscis. c) Uptake of the droplet with the front tarsi and subsequent relocation to the middle tarsi. d) Transfer of the droplet from the middle tarsi to the pollen provisions by moving them upward from the hind basitarsi.