Impacts of GM plants on bees
Science programme: Gene-based insect science
White clover, kiwifruit, apples, canola, seed brassicas, seed onions, and eucalyptus are important honey sources or require bees for pollination. Maize, potatoes and ryegrass are also visited by bees. If GM crops for these varieties become available in New Zealand they may affect bees.
Three issues involving bees and GM plants are:
- Cross-pollination
NZ research on this is described under the heading 'Gene Flow' on the Landcare Research website.
- Occurrence of GM material in honey
Detailed information is available in 'Literature Review on Genetically Modified Plants and Bee Products' on the Ministry of Agriculture and Forestry website.
- Possible impacts on bee health
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.
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