How do GMOs affect insects?

Interview with Dr. Christian Krupke, Professor of Entomology at Purdue University

Beetles, Butterflies, Bees and More: The Relationship Between Bugs and GMOs

There are thousands of insects out there. Beetles, caterpillars, honeybees and many, many more. The average farmer’s field is home to a lot of those insects. Some of them are actually good for the crop, yet a few can be harmful; these are called pests. The good insects are generally those that eat the pests, break down crop residues in the soil or, in the case of the bee, help pollinate many types of fruits and vegetables.

Pests can really damage a crop. In rare cases, they can even ruin an entire field’s produce by eating the crop or killing the plant itself. To combat this, farmers have used a variety of approaches, including the use of pesticides. Pesticides are chemicals that will prevent pests from damaging the plants, either by killing the insect outright or forming a toxic barrier around the plant so that the insect cannot feed on it.

Pesticides have some negative consequences. They add chemicals to the field that can kill beneficial organisms, they’re costly to the farmer and they can be dangerous to certain animals as well as the workers who are applying them. These are some of the reasons why scientists developed genetically modified crops that are pest-resistant. Making the plant itself pest-resistant eliminated or greatly diminished the need for pesticide application on many crops.

How do you make a crop pest-resistant? Scientists were able to modify the plant’s protein manufacturing system so that it now makes a protein that wasn’t previously present. This carefully selected protein is one that is toxic to certain insects. Basically, they eat it and their stomach ruptures. This protein is so specifically targeted towards certain pests that it doesn’t affect other insects, animals or humans that eat it. In fact, it is so specific that it doesn’t even impact "good" bugs, like bees or butterflies.

GM crops don’t harm honeybees or monarch butterflies. On the contrary, they may reduce the need for pesticides that do harm them. Insects that eat genetically modified crops can, in some cases, start to develop a resistance to the protein that usually kills them. This is something to keep an eye on in the future as some GM technologies that work great today will become less effective as certain insects evolve resistance.