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UCSD Scientists Researching Vanishing Honey Bees

Pesticide May Play Role In Colony Collapse Disorder


Imagine a world without apples, almonds and broccoli. It takes honey bees to pollinate most of our favorite fruits, nuts and vegetables -- but the bees are mysteriously disappearing. Some commercial beekeepers in San Diego have already been affected by this phenomenon.

Imagine a world without apples, almonds and broccoli. It takes honey bees to pollinate most of our favorite fruits, nuts and vegetables -- but the bees are mysteriously disappearing. Some commercial beekeepers in San Diego have already been affected by this phenomenon.

Beekeepers are keeping a close eye on the research, some of it at UC San Diego.

The mass disappearance of bee colonies started about four years ago. Scientists believe Colony Collapse Disorder or CCD is caused by a combination of factors, including parasitic mites, a new virus and pesticide exposure.

Alan Mikolich has been a commercial beekeeper since 1985 and has worked with bees for more than 35 years. He maintains hives in San Diego and Riverside counties.

On a sunny July day, he's checking hives near Temecula.

The bees are pollinating nearby wild buckwheat flowers and the hives are dripping with honey.

"See this honeycomb it's been sitting here for awhile, the wax is real light-colored when they first make it, and they seal it over," said Mikolich. "But it's been walked on so it darkened down a little bit. Feel that. There's about five pounds of honey in that."

But Mikolich finds a troubling sign in another hive.

"This could be actually a virus, deformed wing virus," he said, pointing to a honey bee. "This one right here, see how there's no wings to it, just an outline? If you take the one next to it here, see it's got fully-developed wings. That's probably why this hive is weaker than the others."

He finds another bee in the same hive that looks deformed. He said it's likely from a virus or the Varroa mite -- a parasite which sucks blood from developing bees.

Mikolich is not your typical beekeeper. He wears shorts, a short-sleeved shirt and no gloves when he works his hives. He occasionally gets stung, but doesn't seem to mind.

But when it comes to being concerned about Colony Collapse Disorder (CCD), Mikolich is no different than other beekeepers and farmers around the world.

"In the United States one out of three foods that we eat has to have bees for pollination or the plants don't reproduce," said Mikolich. "In California, the most important crop is almonds. And they're 99 percent dependent upon the honey bees in February to pollinate their trees. Without the bees they get no crop."

Mikolich said nearly one million hives -- half of all the beehives in the United States -- are brought into California each year to pollinate the state's almond groves. The U.S. Department of Agriculture statistics show California produces 80 percent of the world's almonds.

The United States could lose $15 billion worth of crops, including California almonds, without bees to pollinate them.

Scientists suggest it's likely the Varroa mite plays a role in CCD. Mikolich and other beekeepers have lost hives because of the mites.

"Oh, I'm very concerned," said Mikolich. "I've lost 50 percent or more five out of the last six years on colony collapse.These parasites and the viruses and the new bacteria's that we have from Asia are just devastating to the the industry at times."

Researchers throughout the world and right here in San Diego are trying to figure out what's happening with the honey bees.

"We have the bees individually labeled and we're watching them inside the nest, to see what they do, how they communicate," said UCSD Professor James Nieh.

The UCSD biologist is trying to determine if certain pesticides affect the bees ability to communicate.

"Because this is a large part of how bees actually pollinate our crops," said Nieh. "A bee finds an almond tree, she actually will go back inside the nest and tell her nest mates where to go to find the almond tree. And if that communication is disrupted, which we think it may be, and some studies suggest it is, that could also have an impact on the health of the colonies."

Nieh said sub-lethal doses of pesticides have been used to kill pests that threaten honey bees but those pesticides may be affecting the bees too. When bees find flowers, a food source, they return to the hive and do a dance to indicate where the food source is located.

Nieh said pesticides may disrupt the process.

"If they are treated with sub-lethal doses of pesticide, they actually will not come back to the nest, they may get lost. and one study suggests they actually will dance less," explained Nieh. "So their efficiency at recruiting other bees to that same food source is decreased and the colony is getting less food into it."

And weaker colonies can mean a greater susceptibility to disease, mites, and bacteria, which are all considered factors in colony collapse.

UCSD graduate student Daren Eiri has been studying the relationship between honey bees and pesticide for three years.

"There is some type of navigational deficit because of the effect of pesticide," said Eiri. "But we need more data to clearly understand the effects of the pesticide and the relationship it has with colony collapse disorder."

He said pesticide may not be directly connected to the disorder but may be one of many factors contributing to it.

For San Diego beekeeper Alan Mikolich, it's been a good honey harvest this season and his bees are, so far, mostly healthy.

But he, along with other beekeepers, biologists and farmers, are paying close attention to the on-going research, which they hope will, one day, provide answers to why the bees are disappearing.

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