By TeVe via WikiMedia Commons
Dr. James Nieh, Associate Professor of Biology at the University of California, San Diego recently described a form of bee communication called the “stop” signal. Foraging bees – ones that leave the hive in search of pollen and nectar – may encounter competition or predators at a food source. When these foragers return to the hive, they convey this information to fellow foragers. (See “Honey bees warn each other about predators at food sources” for more information.) The foragers, now warned that the food source might be dangerous, promptly… returned.
Nieh observed that the bee that receives a stop signal generally returns to the advertised site to “check it out for themselves.” Nieh uses the Internet to explain why the bees would seeming fly directly into the jaws of death (or at least physical peril). “If you hear a rumor from one person,” he explains, “you might not believe it. But if you hear that same rumor from twenty others who have gone out and found the information, you tend to believe the information.” If the forager encounters danger herself, she returns to the hive and does her own stop signaling. More and more bees saying “stop” means fewer bees will go to that deadly patch of flowers. If the danger has passed the bees won’t lose out on a potentially rich source of food.
The subtlety of the response explains why it has taken Nieh over fifteen years to truly understand the stop signal. When Nieh first encountered the stop signal as a senior at Harvard, it was called “begging,” theorizing that the bees were begging for food. However, the “begging” actions didn’t result in the bee receiving food. The stop signal is an example of negative feedback – it decreases the activities of other bees. And behaviors that cause a decreased response are simply harder to study.
Nieh hopes that his insights into the stop signal will give research for negative feedback signals in colonial insects a boost. In any instance where an insect’s actions causes excitement in the hive, Nieh expects to see a response to counteract those signals. For example, when the hive gets too large and needs to swarm, the “let’s fly” messages might have corresponding signals to say “not yet.”