This is the first time I'd heard that a sharp decline in bumble bees have scientists alarmed.

From the article linked below:

The population of bumblebees in the United States is in a kind of free fall, dropping 96 percent over the past two decades, according to a new study that has scientists alarmed.

Four species of bumblebees are in a rapid decline, possibly because of increased fungal infections and inbreeding. Researchers called the findings of the study, published in the Proceedings of the National Academy of Sciences, "disturbing" and said they were in line with findings in Europe.

"Disturbing reports of bumblebee population declines in Europe have recently spilled over into North America, fueling environmental and economic concerns of global decline," the authors wrote.

The bumblebee population in the United States is in a steep decline.The bumblebee is wild, but it pollinates commercial crops from tomatoes to coffee, and its disappearance could have a dire effect on food sources.

"People need to know that wild bees are an enormously important ecosystem service, just like honeybees," Sydney Cameron, the head author of the study and a professor at the University of Illinois, told AOL News by phone today.

More on the link, but I'm surprised that pesticides were not mentioned as a possible cause.

Here is a link that might be useful: US Bumblebee Population in Sharp Decline