The foraging behaviour of honeybees (Apis melli-ferd) and bumblebees (Bombus spp.) on blackcurrant (Ribes nigrum), raspberry (Rubus idaeus) and strawberry (Fragaria × Ananassa) flowers.
Observations on the behaviour of bees visiting black currant, raspberry and strawberry flowers showed that bees touched both stamens and stigmas of nearly every flower visited. Queen bumblebees were more abundant than honeybees on black currants, particularly in cool weather. They worked faster, and visited more flowers per bush and per trip, than honeybees, but like honeybees tended to keep to one row per trip. The honeybee population fluctuated more than that of the bumblebee and reached a peak at about midday. Few honeybees collected black currant pollen, even when their colonies were in black currant plantations. Honeybees were more numerous than bumblebees on raspberries and their numbers fluctuated more. Bees collecting nectar from raspberry flowers acquired pollen incidentally; more than half of them packed it into their corbiculae and the others discarded it. Colonies collected a greater percentage of raspberry pollen near the beginning and end of foraging for the day than during the time of maximum foraging, and the number of bees visiting raspberries increased toward late afternoon. Very few bumblebees visited strawberries. In addition to collecting nectar, and sometimes collecting pollen incidentally, some bees collected pollen deliberately by scrabbling over the anthers, and bees that collected pollen worked faster than those that did not. A bee worked only a small percentage of the open flowers on each plant it visited; nectar-gatherers worked fewer flowers per plant than pollen-gatherers. Honeybee activity increased, in general, with temperature; the number of bees on the crop reached a peak in the early afternoon, and the number of pollen-gatherers and the amounts of pollen collected were greatest near midday.-Rothamsted exp. Stat., Harpenden, Herts.