The nematode, Caenorhabditis elegans, examines its environment and mood to choose whether or not to be a social animal, report Mario de Bono and Cori Bargmann of the University of California at San Francisco, USA, and their colleagues.
"Such complexity may be important to ensure that social behavior is induced only when it offers a selective advantage," the researchers conclude.
In an accompanying article, Marla Sokolowski of the University of Toronto, Canada, states, "The discovery of an association between social behavior and neurons that respond to aversive conditions is exciting".
"It provides a mechanistic basis for observations from behavioral ecology that adverse environmental conditions stimulate the formation of groups".
Also in response to adverse conditions, are the dances which honeybees perform to convey information about the distance and direction of a food source to fellow bees.
|Social behavior is induced only when it offers a selective advantage.|
Originally, these were thought to increase colony food collection.
However, researchers from the University of California at Riverside, USA, found that the dance sometimes increases the amount of food collected, but at other times makes no difference.
"The dance appears to come into its own when a food source is hard to find, or ephemeral", they conclude.