University of Illinois at Urbana-Champaign Jan. 3, 2011, press release:
A three-year study analyzed the geographic distribution and genetic diversity of eight species of bumble bees in the U.S., relying on historical records and repeated surveys of about 400 sites. The researchers compiled a database of more than 73,000 museum records and compared them with current sampling based on intensive national surveys of more than 16,000 specimens.
The national analysis found that the relative abundances of four of the eight species analyzed have declined by as much as 96 percent and that their surveyed geographic ranges have shrunk by 23 to 87 percent. Some of these contractions have occurred in the last two decades.
Researchers have many hypotheses about what is causing the declines, but none have been proven. Climate change appears to play a role in the declines in some bumble bee species in Europe. Habitat loss may also contribute to the loss of some specialist species, she said. Low genetic diversity and high infection rates with the parasite pathogen are also prime suspects.
Read more here.
IMAGE by Janet Sinn‑Hanlon of the Imaging Technology Center, Beckman Institute, University of Illinois