SAN FRANCISCO (KCBS)— Central Valley beekeepers are losing tens of thousands of dollars to thieves making off with beehives. This is a double-whammy for beekeepers who are already having a hard time keeping their colonies alive.

It’s estimated that honeybees add $15 billion to the value of the nations crops each year, they’re particularly valuable to Central Valley almond orchards where during pollination season in late winter, half of the nation’s colonies are set up.

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But with a third of the colonies dying off each winter, thefts of beehives are on the rise.

Dennis Van Engelsdorp is an entomologist at the University of Maryland said it’s insult to injury because beekeepers have been losing 30 percent or better of their colonies every year on average.

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“Often these beekeepers have struggled to get these colonies into the orchards and then to have some stolen, really hurts them because they’re having such a hard time staying economically viable,” he said.

However, he doesn’t suspect that there’s a black market for beehives.

“I do think that they probably are being stolen by other people who know how to keep bees perhaps to replace their dead outs. Beekeepers often brand their hives so you can see the name outside and you’ll often see discarded boxes where they’ve just taken the guts of the hive with the bees and move them into other labeled boxes,” he said.

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Bee colonies worldwide have been affected by a phenomenon called Colony Collapse Disorder (CCD), in which entire beehives die at once. A recent study by scientists at the University of Maryland and the U.S. Department of Agriculture showed a toxic mix of pesticides and fungicides contaminating pollen that bees collect for their hives. Those bees ingesting the pollen were more likely to be infected by a parasite implicated in CCD.