By Charlotte Dormer (Plante Earth Online - June 12, 2012)
Exposure to pesticides can harm bumblebee reproduction, research has shown. Scientists think the pesticides cut feeding rates, leading to fewer offspring being produced.
Scientists already knew that neonicotinoid pesticides, which affect insects' nervous systems, can alter bee behaviour, putting these vital pollinators, already threatened by habitat loss and disease, further at risk.
This new piece of research shows that bumblebees with diets contaminated with levels of neonicotinoid pesticide typically found in the environment produce up to a third fewer offspring.
The scientists looked at other ways that neonicotinoids could have affected reproduction. They found the pesticides do not damage the development of ovaries or delay egg-laying, except at really high doses. But they noticed that the more pesticide a bumblebee ingested, the less pollen and syrup it ate. So exposed bees...