ABC News reports today that researchers have documented a 96 percent decline in the numbers of four previously abundant species of bumblebee in the United States in a study confirming that the agriculturally important bees are being affected worldwide.
Several reports have documented the disappearance of bumblebees in Europe and Asia, but no one had done a large national study in the Americas.
"These are one of the most important pollinators of native plants," Sydney Cameron of the University of Illinois, Urbana, who led the study, said in a telephone interview to ABC. The report in the Proceedings of the National Academy of Sciences called the findings "alarming."
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.