QAre there any legitimate studies indicating that bees are being affected by Bt crops?

Are there any legitimate studies indicating that bees are being affected by Bt crops?

AExpert Answer

Thank you for your question. First, the insecticidal protein the crop produces is very specific to particular insect orders. For example, the Bt protein Cry1Ab affects only specific caterpillar (the order Lepidoptera) pests, while the Bt protein Cry3Bb1 affects only specific beetle (the order Coleoptera) pests. This specificity is one of the reasons Bt is such a popular insecticide in both GM crops and non-GM crops, including organic agriculture. Thus, the Bt proteins currently being used in crops do not affect bees (the order Hymenoptera).


For more information on Bt specificity, please see these related responses here and here.


Secondly, all commercial Bt insecticidal proteins are tested by specifically feeding the Bt protein to honey bee larvae (immatures) and honey bee adults. Scientists compared the results of bees fed the Bt insecticidal protein with bees fed a diet without the protein. In some studies, the Bt protein is plant derived (i.e., the pollen or leaf tissue is part of the diet), and in other studies, the protein (Cry1Ac, for example) is used in the diet. Three papers in scientific journals (Apidologie, the Annual Review of Entomology and PLoS ONE) reviewed the published data from 32 different trials. All three papers concluded that bees are not affected by Bt. A review by Malone and Pham-Delègue (2001) looked at seven studies. Their conclusion was that “Bt transgene products are very likely to be safe for honey bees and bumblebees.” One large study by, Duan et al. (2008), looked at 25 different studies and concluded that “the Bt Cry proteins used in genetically modified crops for control of caterpillar and beetle pests do not negatively affect the survival of honey bee larvae or adults in the laboratory.” The third paper, by O’Callaghan et al. (2005), stated, “Other studies with bees fed purified Bt proteins, or pollen from Bt plants, or bees allowed to forage on Bt plants in the field, have confirmed the lack of effects noted by the U.S. Environmental Protection Agency (EPA).”


Finally, there are studies that, upon first glance, seem to indicate that GM crops affect bees, when actually it’s not the crops at all that are responsible, but other production factors. For a good example of this, read the Morandin and Winston study (2005). This study shows that fewer wild bees were found in the GM canola studied, but the authors concluded the decline was due to fewer weeds in the GM crop, compared with a conventional or organic canola crop.

Posted on July 28, 2017
Hummingbird feeders often contain a sugar solution that is similar to plant nectar. Therefore, bees are attracted to these Hummingbird feeders, because similar to hummingbirds, the sugar/nectar attracts them. There are some hummingbird feeders on the market that are designed to prevent bees, ants, and other insects from getting in.   Bee decline is complex and often misunderstood by the public. Chris Sansone, Global Regulatory Affairs Manager of Insect Resistance Management (... Read More
Posted on August 15, 2017
GMO crops are not "banned" in any countries around the world in the normal sense of that word. Usually when something is banned for consumption, etc., it is because some problem emerged that needed a response. The history of regulation for biotech crops is quite different in that there were regulatory approval processes developed long before any such crops were commercialized. The goal was to try to anticipate any potential health or environmental issues and to make... Read More
Posted on February 9, 2017
A species is defined by the ability to reproduce viable offspring, so any two plants within a species generally have the potential to cross pollinate. Like any good successful mating, it requires the union of male and female contributions at the right time, same place. So absolutely, GE crops have the potential to cross with non-GE crops of the same species—if they manage to get it on through time and space.    So the rules that apply to dogs and teenagers also apply to... Read More