The pesticide has been used in rapeseed fields and controlled groups of bees have been set in those fields.
Globally, neonicotinoids is one of the most common pesticides used against insect pests. In Sweden it was used for crop protection. It is not known how much of this susbtance can be left on the plant and if it will harm bees.
"The potential problem is that bees and bumblebees orientation can be damaged. Bees are social insects . So even small disruptions in their navigation skills and ability to communicate with one another can get pretty serious consequences," says Thorsten Rahbek Pedersen, the project manager of the study.
The EU Commission has now banned three types of neonicotinoids for two years, to allow time for more research on the suspected link between the substances and the mass death of bees. The manufacturers believe the ban is unfounded and has sued the European Commission.
Seven years ago, bee colonies began to die en masse in North America and also in Europe. Deaths of bees not only mean less honey, but also smaller agricultural yields because of the lack of bees can pollinate the plants.
The Swedish study is a collaboration between the Board of Agriculture, several universities, and several associations of beekeepers and farmers.
96 bee and bumble bee colonies were placed on 16 rapeseed fields in southern Sweden.