In recent years, experts have documented a disappearance of bees in what is widely called colony collapse disorder, blamed on many factors including parasites, fungi, stress, pesticides and viruses. But most studies have focused on honeybees.
Bumblebees are also important pollinators, Cameron said, but are far less studied. Bumblebees pollinate tomatoes, blueberries and cranberries, she noted.
As with honeybees, a pathogen is partly involved, but the researchers also found evidence of inbreeding caused by habitat loss.
To read more on colony collapse disorder and for guidelines on how farmers across the U.S. are making their land more bee-friendly, see our Summer 2010 World Ark article "Beauty and the Bees" by Sarah Schmidt.
Photo by Eric Mader, Xerces Society