A pest-eating ladybug attacks an aphid.
As angry debates about genetic modification continue, GM crops are quietly going about their business—and producing some positive side effects. In China, with Bt cotton reducing the need for insecticides, pest-eating bugs have rebounded and brought natural pest control with them.
China’s genetically modified cotton is not new. Farmers used to spray their cotton with a protein, naturally produced by the Bacillus thuringiensis (Bt) bacteria, which is toxic to certain insects. As research into genetically modified crops advanced, scientists implanted the cotton itself with the Bt genes that code for production of the insect toxin, creating so-called “Bt cotton” and alleviating the need for the sprayed insecticide. Since China approved its use in 1997, Bt cotton has proved itself particularly effective against the cotton bollworm moth, reducing the costs and side effects of spraying pesticides, but it has had may also decrease the number of non-pest insects compared with organic fields.
With the advent of Bt cotton, pesticide use became specialized, only affecting insects that both were vulnerable to Bt’s toxin and that fed on cotton, which allowed the populations of other insect species to rebound. Some of the now-thriving species, like mirids, are pests, but others eat pests, and their recovery is making natural bug control possible.
What’s the News: We’ve all probably heard the myth, made popular by Disney’s Dumbo, that elephants are afraid of mice. While that idea may not be exactly true (video), elephants do make sure to avoid another tiny critter: bees. Knowing this, zoologists from the University of Oxford loaded fences in Kenya with beehives, in hopes of deterring roaming African elephants from eating or trampling farmers’ crops. Now, two years later, the researchers are reporting in the African Journal of Ecology that the novel barriers are working wondrously and could be a viable option for protecting African croplands.
What’s the News: As human societies adopted agriculture, their people became shorter and less healthy, according to a new review of studies focused on the health impacts of early farming. Societies around the world—in Britain and Bahrain, Thailand and Tennessee—experienced this trend regardless of when they started farming or what stapled crops they farmed, the researchers found.
This finding runs contrary to the idea that a stable source of food makes people grow bigger and healthier. The data suggest, in fact, that poor nutrition, increased disease, and other problems that plagued early farming peoples more than their hunter-gatherer predecessors outweighed any benefits from stability.