Frigid winter temperatures played a role, but disease is a bigger factor in the losses suffered by Wisconsin beekeepers. Some report the loss of 80 percent of their bees. One expert says mites cause the diseases which are wiping out some hives. He says scientists are trying to raise queen bees which are more resistant to mites. The losses have hit hobbyists harder than the professionals, who have developed ways to protect their bees over the years.