Research finds bees contribute to yields of wind-pollinated oilseed rape

Photo by Frank Mikley via Wikimedia Commons.

Photo by Frank Mikley via Wikimedia Commons.

Bees are contributing some €4 million annually to the Irish economy by facilitating the pollination of oilseed rape, researchers in Trinity College Dublin have found.

One of two research papers from the Trinity Centre for Biodiversity Research exploring the role of bees in boosting yields of oilseed rape — an increasingly important crop here due to the rise in demand for pure plant oil and its potential for use as an alternative to fossil fuels — found that foraging bees contribute significantly to yields of the plant, which is primarily pollinated by the wind. When bees were prevented from feeding on the plants’ bright yellow flowers, seed production in the crop was found to be reduced by an average of 27 per cent.

A second paper details the diversity of flying insects found among oilseed rape crops, which includes several species of bees, hoverflies and beetles.

“Oilseed rape fields are full of pollinators, including honeybees, bumblebees, solitary bees and hoverflies,” said Jane Stout, associate professor in Botany at Trinity, and director of the Trinity Centre for Biodiversity Research, who was the principal investigator on both papers. “Although many people think of the honeybee as being our main pollinating species, bumblebees and hoverflies are also important pollinators of oilseed rape crops. We found hundreds of bees, especially in spring oilseed rape, where we estimated on average 600 to 800 colonies of bumblebees alone using the pollen and nectar from just one field.”

The research tends to indicate that the large-scale production of oilseed rape has less impact on insect biodiversity than expected, though researchers have cautioned that the crop could have a greater impact if grown on a larger scale than was investigated, and recommend interspersing crops in a patchwork pattern to promote insect diversity and the concomitant benefits of insect pollination.

The European Union recently moved to restrict the use of neo-nicotinoid pesticides on oilseed rape crops; these pesticides have been implicated in colony collapse disorder, which has seen a significant decline in several bee species in Europe and North America.

According to researcher Dara Stanley, who worked with Prof Stout on these projects, the newly discovered benefit that bees provide in pollinating crops normally associated with wind pollination should provide further incentive to conserve bees in agricultural areas.

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