© Georg JanderAn aphid that is attacked by a ladybug releases an alarm pheromone that causes nearby aphids to flee from danger.
Similarly, when aphids are raised on plants genetically engineered to emit a compound that warns surrounding aphids of a predator, they become accustomed to the chemical and no longer respond to it -- even when a predator is present, according to Cornell and Boyce Thompson Institute (BTI) researchers reporting Aug. 3 in an online edition of the Proceedings of the National Academy of Sciences.
Under normal circumstances, when a ladybug captures and bites into an aphid, the victim releases an alarm pheromone called beta-farnesene, which prompts nearby aphids to walk away or drop off the plant. Researchers are interested in protecting plants from aphids through genetically engineered crops that produce beta-farnesene or through traditional breeding methods that cross crops with plants -- such as some wild and cultivated potatoes and peppermint -- that naturally produce the pheromone.
The findings have implications for controlling aphids in crops, which could be engineered to make aphids unresponsive to warnings of ladybugs and other predators, making them easy prey.
