|June 28, 2012
Genetically modified crops are often designed to repel hungry insects. By having toxins built into the plant itself, farmers can reduce their use of environmentally unfriendly insecticide sprays. But as any first-year evolutionary biology student can tell you, insects are like the Borg in Star Trek: they quickly adapt. And this is precisely what is happening – but in ways that have startled the researchers themselves.
The discovery is a wakeup call to geneticists because it has highlighted the importance of having to closely monitor and counter pest resistance to biotech crops. The development also raises the question of the potential futility of having to change the genetic structure of crops in perpetuity; given that insects are constantly evolving, to what degree will geneticists have to go to ensure crop immunity to pests? And what does that say to the ongoing safety of such crops as far as human consumption is concerned?
Case in point are cotton bollworms. To deal with these pests, genetic scientists have developed an insect-killing cotton plant that produces toxins derived from the Bt bacterium (geneticists say that these toxins are harmless to most other creatures, including humans). But the bollworms are developing a resistance. Scientists have observed that a rare genetic mutation in bollworms makes them immune to Bt – and that the mutation isn't so rare any more.
One scientist who predicted that these insects would adapt is Bruce Tabashnik, head of the department of entomology at the University of Arizona College of Agriculture and Life Sciences and co-author of the study making note of these findings. To stay ahead of the game, Tabashnik studied bollworms in the lab just to see how they would adapt to the toxin. Then, expecting to see the same sorts of adaptations in the real world, he took a look at bollworms in China.