Now researchers at U.C. Davis and in Toronto may have found clues to what is killing off the bees.
Honeybees are vital to California agriculture and yet honeybees have been disappearing at an alarming rate. It's what's called 'colony collapse disorder.'
Adult bees leave the hive, then baby bees die, which leads to the death of colonies. It has brought an increase in research at U.C. Davis, one of the top bee schools in the country. They think it could be caused by environmental factors like stress, bad diet and infection.
"There's a concentration of certain diseases in any particular colony and sometimes one virus is off the wall. Sometimes another virus is. Sometimes it's a fungal disease. It just looks like the bees are weak and when one or another of these things comes along it apparently can reach overwhelming amounts," said U.C. Davis Bee specialist Eric Mussen.
So far bee keepers have been able to breed and recover colonies. There is another factor according to Canadian research.
Commercially-raised bumblebees are used to help pollinate crops in greenhouses. But trouble arises if they escape captivity and mix with their wild cousins. Researchers are finding commercially-bred bumblebees are not as healthy as those in the wild.
"We found that these bees harbored incredible loads of disease. The same bees that are used in greenhouses are in fact very sick bees and carry many parasites that you don't see at nearly the same levels in wild populations," said Michael Otterstatter of the University of Toronto.
He developed a mathematical model to predict how one specific parasite might spill over from commercial to wild bees. The parasite harms a bee's ability to think and find food, leading to starvation.
Now they need to come up with a way to block the parasite. U.C. Davis researchers are cross-breeding domestic honeybees with European bees hoping to produce a resistant strain.
The company that is certainly taking a lead in saving bees is the Bay Area's Haagen Dazs. They need fruit and almonds for their ice cream.
