Monday, June 21, 2010

Are gm crops causing a decline in bumble bee numbers?

I read that it was a virus that was killing the bee population - we should all be very afraid.Are gm crops causing a decline in bumble bee numbers?
There is a possible mechanism by which GM will affect bees. If GM crops are infertile and produce flowers but do not pollen, they may find problems feeding in the area. This may also apply to infertile garden cultivars. However, I do not know of any such commercial crops. I do know that pesticides will either kill or injure the insects and the survivors will be more susceptible to viruses and mites as a result.

Over 30% of our crops rely on bees for pollination, so there demise would be very serious, in my view. Are gm crops causing a decline in bumble bee numbers?
I think its to do with the recent rather wet weather bouts we are having that are keeping them in the hives, and then as someone else has said there is also a nasty virus that is going around which is being particularly effective because they are not leaving the hives as much.

But hey, who knows the GM crops may not be helping.
When considering the potential impacts of GM plants on bees, it is important to remember that bees eat only pollen, nectar, resins (for propolis) and honeydew (excreted by sap-sucking insects); they do not eat leaves, stems or roots. Therefore a GM plant can only affect a bee if it expresses a novel protein in the parts that bees eat and if that protein has biological activity against the honey bee.

We have studied the effects that plants expressing different proteins may have on bees without using GM plants. We fed purified novel proteins, identical to those produced by GM plants, at a range of concentrations, to adult and larval bees kept in the laboratory.

We measured the effects of three classes of proteins on bees:

Bt toxins (designed mostly to control caterpillars), and found no effects

Protease inhibitors (for caterpillar and beetle control), and found only slight effects at very high concentrations

A biotin-binding protein (for general insect control), and found no effects.

Overseas colleagues working with GM plants and bees have found that most GM plants produce only minute quantities of novel proteins in pollen and none in nectar. They have found no negative effects on bees from plants modified to be insect- or herbicide- or disease-resistant.

Our team has carried out research on bee health since 1995. We have worked closely with colleagues overseas in a co-ordinated research effort.

For more information see EDP Sciences website or download a copy of the review paper 'Effects of transgene products on honey bees and bumblebees' in PDF format.

Hi Kit,

I don't think we can blame GM crops this time. Honey bees are the main pollinators of food crops, as they stick to one crop at a time, while bumble bees go randomly. I wondered if it could be the same thoracic mite that was killing off the honey bee, and I found this interesting article (link below). It is a parasite that robs bees of the ability to distinguish which flowers have nectar and which don't. The bee starves to death slowly by visiting empty flowers. I'm glad you asked this question and helped me learn something. I'll be a lot more tolerant of them buzzing me while I'm tending their flowers!鈥?/a>

Kit, I just found an article by a guy in Germany who says that toxins from bt corn DO make the bees more suseptible to the parasite. Just google ';gm crops + bees'; to see several opinions.
A little bit, but most is due to systemic pesticides that flow through the sap of the plant. When the bees feed on the nectar of the flowers they get poisoned.

Imidacloprid is a common bee killing pesticide that has been pushed onto farmers to kill pest insects.
I don't think that GM is having an affect on bees, there's not enough of it. What is causing a problem is Verroa, a mite and parasite.鈥?/a>
Gawd, I hope not. I thought the current theory was that it's something to do with mobile masts interfering with their navigation system.

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