more on the bee die off

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From Humans To : Could Genetic Modification Be Killing The Bees?

Added: Mar 11th, 2007 11:56 AM

 

Could genetically modified crops be killing bees?

John McDonald, Special to The Chronicle

 

With reports coming in about a scourge affecting honeybees, researchers are

launching a drive to find the cause of the destruction. The reasons for rapid

colony collapse are not clear. Old diseases, parasites and new diseases are

being looked at.

 

Over the past 100 or so years, beekeepers have experienced colony losses from

bacterial agents (foulbrood), mites (varroa and tracheal) and other parasites

and pathogens. Beekeepers have dealt with these problems by using antibiotics,

miticides or integrated pest management.

 

While losses, particularly in overwintering, are a chronic condition, most

beekeepers have learned to limit their losses by staying on top of new advice

from entomologists. Unlike the more common problems, this new die-off has been

virtually instantaneous throughout the country, not spreading at the slower pace

of conventional classical disease.

 

As an interested beekeeper with some background in biology, I think it might be

fruitful to investigate the role of genetically modified or transgenic farm

crops. Although we are assured by nearly every bit of research that these

manipulations of the crop genome are safe for both human consumption and the

environment, looking more closely at what is involved here might raise questions

about those assumptions.

 

The most commonly transplanted segment of transgenic DNA involves genes from a

well-known bacterium, bacillus thuringiensis (Bt), which has been used for

decades by farmers and gardeners to control butterflies that damage cole crops

such as cabbage and broccoli. Instead of the bacterial solution being sprayed on

the plant, where it is eaten by the target insect, the genes that contain the

insecticidal traits are incorporated into the genome of the farm crop. As the

transformed plant grows, these Bt genes are replicated along with the plant

genes so that each cell contains its own poison pill that kills the target

insect. [Oh yum, NOT!]

 

In the case of field corn, these insects are stem- and root-borers,

lepidopterans (butterflies) that, in their larval stage, dine on some region of

the corn plant, ingesting the bacterial gene, which eventually causes a

crystallization effect in the guts of the borer larvae, thus killing them.

 

What is not generally known to the public is that Bt variants are available that

also target coleopterans (beetles) and dipterids (flies and mosquitoes). We are

assured that the bee family, hymenopterans, is not affected.

 

That there is Bt in beehives is not a question. Beekeepers spray Bt under hive

lids sometimes to control the wax moth, an insect whose larval forms produce

messy webs on honey. Canadian beekeepers have detected the disappearance of the

wax moth in untreated hives, apparently a result of worker bees foraging in

fields of transgenic canola plants.

 

Bees forage heavily on corn flowers to obtain pollen for the rearing of young

broods, and these pollen grains also contain the Bt gene of the parent plant,

because they are present in the cells from which pollen forms.

 

Is it not possible that while there is no lethal effect directly to the new

bees, there might be some sublethal effect, such as immune suppression, acting

as a slow killer?

 

The planting of transgenic corn and soybean has increased exponentially,

according to statistics from farm states. Tens of millions of acres of

transgenic crops are allowing Bt genes to move off crop fields.

 

A quick and easy way to get an approximate answer would be to make a comparison

of colony losses of bees from regions where no genetically modified crops are

grown, and to put test hives in areas where modern farming practices are so

distant from the hives that the foraging worker bees would have no exposure to

them.

 

Given that nearly every bite of food that we eat has a pollinator, the

seriousness of this emerging problem could dwarf all previous food disruptions.

 

This article appeared on page F - 4 of the San Francisco Chronicle