Wild colonies also produce males, which also visit flowers to feed and so can pollinate them with pollen carried on their bodies. It is feasible to produce colonies consisting mainly of male bumblebees and, because the males have no sting, such colonies should lessen the fears of glasshouse workers, especially those who are allergic to bee stings.
In the experiments reported here, male buff-tailed bumblebees (Bombus terrestris L.) and male red mason bees (Osmia rufa L.) were bred in the laboratory.
The blackcurrant cultivar 'Ojebyn' was chosen as the model insect-pollinated plant as it can also be self-pollinated. In three treatments, flowering shoots were enclosed in gauze sleeves, into each of which either one male bumblebee, one male red mason bee, or no bees were introduced.
The flowering shoots of the fourth treatment were not covered, which allowed their flowers to be pollinated by any free-ranging insect.
Self-pollination produced the fewest fruit per inflorescence, while pollination by male bumblebees produced the most, closely followed by pollination by free-ranging insects. The male bumblebees achieved 79 per cent pollination, which suggests that as well as pollinating blackcurrants, they could also be used to pollinate other crops grown in plastic tunnels and glasshouses.
Dr Ken Cockshull, Associate Fellow, Warwick Crop Centre, University of Warwick
The Importance of Male Red Mason Bee (Osmia rufa L.) and Male Buff-Tailed Bumblebee (Bombus terrestris L.) Pollination in Blackcurrant (Ribes nigrum L.) by Fliszkiewicz, Giejdasz and Wilkaniec (2011). Journal of Horticultural Science & Biotechnology 86 (5): 457-460.