Insecticide link to drop in wild bee population
THE decline in wild bee populations across the countryside has been directly linked to a controversial type of insecticide.
Exposure to oilseed rape crops treated with chemicals known as neonicotinoids cut the populations of 62 wild bee species south of the Border between 2002 and 2011, a study shows.
The insecticides are applied to the seed before planting to stave off pests such as aphids and root-eating grubs. However, they remain in the plant as it grows, which means bees harvesting the plant’s pollen will ingest the chemical.
Though not normally present in big enough quantities to cause acute harm, the insecticides have been linked to chronic problems with bee populations. The latest research, the largest and most comprehensive of its kind, was carried out by the Centre for Ecology and Hydrology.
It shows that although the fall in bee numbers could be attributed to several factors, bees which regularly fed on rape crops declined by three times as much.
Neonicotinoids are banned by the EU and the European Food Safety Authority is reviewing their use.
For five of the species investigated neonicotinoid use was linked to at least 20 per cent of local population extinctions.
Dr Ben Woodcock, the study’s lead author, said: ‘This is the strongest correlative evidence yet that we have seen for the negative impact of neonicotinoids on bee presence.’