Solitary bees are twice as likely to pollinate the plants they visit as bees from colonies.

Following a two month investigation in Wiltshire, which examined bees' behaviours around oilseed rape flowers, scientists from the Centre for Ecology and Hydrology (CEH) suggested solitary bees visiting the plants' flowers will leave pollen in 71 percent of cases.

However, bumblebees and honeybees spent a shorter period of time on flowers, and were found to be less likely to have pollen on their bodies. Honeybees also made less contact with flowers' stigmas, which collect pollen.

The researchers said their findings illustrate the vital need to protect wild bee species, in order to provide "back-up pollination services to our struggling honeybee colonies." CEH spokesperson and study leader Dr Ben Woodcock said, "Underlying all of this is a lack of honeybees. There simply aren't enough honeybee colonies in the UK to effectively pollinate all of our crops. They're not going to do it alone; they need support from wild bee populations."

Dr Woodcock added that, as commercial honeybees are kept with the aim of creating honey, not pollinating crops, their distribution doesn't favour pollination. He suggested wild bees living away from densely populated hives could have a significant impact on pollination.

Honeybee populations have fallen in the UK in recent years. This is partly due to reductions in the number of managed colonies, though figures released last week by the British Beekeepers Association revealed honeybee colony losses over winter 2012/2013 were at their highest point since its winter survival survey began.

BBKA estimates that a third of all honey bee colonies were lost last winter – more than double the losses of the previous year. Increased losses were recorded in all regions of England. The Association blamed poor weather over the past 18 months for the high losses.

Dr Woodcock advised driving the creation of more species-rich grasslands, growing wildflowers in field margins to provide food outside of crops' flowering period and protecting other habitats that favour bees and their fellow insect pollinators.

Since the beginning of the year, the EU's risk assessment watchdog EFSA has also recommended tightening up risk assessments and restricting use of certain pesticides to ensure that wild bees are protected from their potentially damaging effects.