Bees Boost Irish Economy

Researchers from Trinity College Dublin have shown that bees contribute almost €4 million to the Irish economy each year, simply by improving seed production in crops of oilseed rape.

Known for its brilliant yellow flowers, oilseed rape is being grown to an increasing extent in Ireland as farmers respond to a heightened demand for pure plant oil. This oil is an important source of biofuel and could ultimately reduce our reliance on non-renewable fossil fuels as we seek greener, more environmentally friendly solutions to energy demands.

The crop is pollinated adequately by the wind, but, for the first time in Ireland, researchers were able to show that foraging bees transferring pollen from flower to flower greatly boost the all-important yield. When bees were experimentally excluded from visiting the flowers, seed production was, on average, 27% lower than when they had open access.

This discovery, which will soon appear in the international Journal of Insect Conservation, added to related findings that were reported in another article in the journal GCB Bioenergy. Both papers sprang from research conducted as part of the Sectoral Impacts on Biodiversity and Ecosystem Services (SIMBIOSYS) initiative, which received €1.6 million in funding from the Environmental Protection Agency over a five-year period.

In addition to the discovery that bees are important assets to oilseed rape farmers, the previous paper showed that these fields were buzzing with insect life comprising many species of bees, hoverflies and beetles.

Associate Professor in Botany at Trinity, and Director of the Trinity Centre for Biodiversity Research, Jane Stout, who was the principal investigator on both papers said: “Oilseed rape fields are full of pollinators, including honeybees, bumblebees, solitary bees and hoverflies. 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 600-800 colonies of bumblebees alone using the pollen and nectar from just one field.”

The diversity and sheer volume of pollinators in oilseed rape crops came as something of a happy surprise, because some reports had previously suggested that swathes of the plant might discourage farm-friendly insects. However, researchers caution that different patterns could arise when the crop is grown on a larger scale than was investigated. They also recommend interspersing fields that grow food and biofuel crops in the hope that such a patchwork quilt-like pattern will promote insect diversity and enhance the precious pollination service provided by the critters.

Researcher Dara Stanley, who worked with Stout on these projects, added: "Oilseed rape crops in Ireland are expanding hugely, and, if they benefit from pollination, this is both good news for farmers, and an incentive to conserve bees in agricultural areas.”

One major threat to bees comes from the use of certain pesticides called neo-nicotinoids, which have been implicated in recent declines of many species throughout Europe and North America. An EU ban preventing the use of these pesticides on oilseed rape was recently agreed, which will hopefully help the bees of Ireland keep up their good work in our farmers’ fields. However, there are concerns that use on other crops, which is still permitted, will negatively affect our furry friends.

Radio transmitters used to track bees

A group of scientists have used minute radio transmitters to track the movements of bees as they track down rare flowers.

It is the first example of the successful use of micro radio telemetry to track movement of an insect pollinator and the results may have implications for our understanding of biological activity patterns and the evolution of forset pollinators.

The iridescent blue-green orchid bees (Exaerete frontalis) were fitted with  transmitters weighing just 300 mg. Eyelash adhesive was used to attach the equipment to the bee's thorax (see image above).

A total of 16 bees were tagged (four were lost) and the team was able to track them for about 5 days. The results confirmed that such large orchid bees have very large home ranges and averaged about 45 hectares (although one of the bees had a range of 700 hectares).

The scientists warn that the results must be interpreted carefully but "by extending radio telemetry to bees that are scarcely a few times heavier than transmitters we obtained credible results because orchid bees are known for their flight capabilities".

These results were published in PLoS ONE journal and can viewed in its entirety here.