Worm's social feeding linked to human obesity.

• Position: Biodiversity

Scientists at the University of Texas Southwestern Medical Center at Dallas and the University of California, San Francisco, have shown that the feeding behavior in worms is controlled by neurons that detect adverse or stressful conditions. The discovery of the gene that controls social feeding behavior in worms was made in 1998. The new findings build on the earlier research by identifying the nociceptive neurons--those that transmit pain signals--triggering group feeding.

"The gene that controls this behavior in worms is like the one that controls feeding in humans," points out Leon Avery, associate professor of molecular biology at UT Southwestern. "The epidemic of obesity in America makes [these findings on neurons] potentially relevant to health."

Scientists have long known that soil worms, called Caenorhabditis elegans, have varying eating habits. The species of the worm commonly used in research labs tends to feed alone. In the wild, however, most of the C. elegans feed in groups. "It's like they're having a party," Avery notes. "Other worms pay no attention to each other when there's food" around.

In higher species, factors such as season, availability of food, and natural enemies can regulate aggregation behavior, which in turn can...