Scientists examine how common pesticide mixes may affect bee die-offs

Oct 29, 2009 by Stu Hutson

(PhysOrg.com) -- Since reports of widespread bee die-offs began to surface in October 2006, researchers have investigated possible reasons ranging from hive-infecting mites to cell phone-tower radiation. They have yet to pinpoint the cause of colony collapse disorder -- most likely, because there isn’t just one, say University of Florida researchers.

The mysterious die-offs are likely a result of an accumulation of factors, which might include chemicals found in and around the hives, they say.

Led by UF Institute of Food and Agricultural Sciences bee specialist Jamie Ellis, the researchers have finished a first round of testing on bee exposed to the pesticides most commonly found in bee hives. The work gives crucial insight to how the larvae react to these pesticides, which are usually only tested on adult bees.

More importantly, the work sets the stage for the researchers to test how the bees react to combinations of these pesticides.

Just like mixing the wrong medications can have deadly and unpredictable results in humans, chemical mixes pose a quandary for the bee industry. Bees are commonly exposed to multiple pesticides that are either applied to or nearby their hives.

“Beeswax, honey and pollen can contain low mixtures of fungicides, insecticides, and . The larvae develop in the presence of and consume these mixtures,” Ellis said. “Any one of these pesticides may not be that harmful to the developing larvae. However, it is possible that combinations of the pesticides can interact.”

The U.S. bee industry is responsible for pollinating $15 billion worth of crops each year. By some estimates, bee pollination is responsible for as much as a third of the food we eat.

The work, funded by the North American Pollinator Protection Campaign, would be among the first to look at such combinations of chemicals introduced at the larval stage. At an Oct. 22 meeting of NAPPC, Ellis presented the initial results, which examined the individual effects of two herbicides, two fungicides and five insecticides commonly found in bee hives.

To study these pesticides, the researchers transferred individual larvae to special containers where they were given a typical diet containing a dose of the pesticide.

Some of the pesticides yielded surprising results. For example, the bees seemed to show an erratic response to two commonly used to get rid of hive-infecting Varroa mites. This could mean that some bees have become resistant to the pesticide while others have not, said Mike Scharf, a UF entomologist and co-primary investigator on the project.

“There’s a really complex and unpredictable interaction of chemicals and genetics at play,” Scharf said.

Even more so, he said, when the bees are exposed at the larval stage. Pesticide exposure at this developmental stage could have significant effects on the adult bees.

Later research will reintroduce these adult bees into the hive to see how the pesticide-exposed bees react to common stressors such as Varroa mites and bacterial infections.

“It is going to be a lot of work to run through all these scenarios, but at the end of the day, it’s the only way to really find out how all these factors come together,” Ellis said. “It’s worth the work. are a fundamental part of our ecosystem and our food chain.”

Provided by University of Florida (news : web)

Explore further: Feline fame in cyberspace gives species a boost

add to favorites email to friend print save as pdf

Related Stories

Fungus Foot Baths Could Save Bees

Jul 28, 2008

One of the biggest world wide threats to honey bees, the varroa mite, could soon be about to meet its nemesis. Researchers at the University of Warwick are examining naturally occurring fungi that kill the varroa mite. They ...

Pesticide build-up could lead to poor honey bee health

Aug 18, 2008

Honey bees industriously bring pollen and nectar to the hive, but along with the bounty comes a wide variety of pesticides, according to Penn State researchers. Add the outside assault to the pesticides already ...

Probing Question: What's killing the honey bees?

Mar 01, 2007

Far away from the snowdrifts outside our windows, spring is unfolding in California as the almond trees begin to bloom. Missing from the party are millions of honey bees typically trucked in to pollinate the ...

Asian bees threaten Australia

Jun 15, 2007

Four swarms of Asian bees found in Cairns, Australia, may pose a serious threat to the country's honey bee population.

Bee keepers across U.S. suffering losses

Apr 24, 2007

Beekeepers across the United States are noticing a large loss in hives from year to year and it is being attributed to colony collapse disorder.

Scientists search for cause of bee deaths

May 14, 2007

A U.S. scientist says parasites, pathogens and pesticides are all possible suspects in the recent staggering decline in the number of the world's honeybees.

Recommended for you

The ants that conquered the world

Dec 24, 2014

About one tenth of the world's ants are close relatives; they all belong to just one genus out of 323, called Pheidole. "If you go into any tropical forest and take a stroll, you will step on one of these ...

Ants show left bias when exploring new spaces

Dec 23, 2014

Unlike Derek Zoolander, ants don't have any difficulty turning left. New research from the University of Bristol, UK published today in Biology Letters, has found that the majority of rock ants instinctively go lef ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.