Evidence of social facilitation and inhibition in digging behavior of red imported fire ants, Solenopsis invicta.

Abstract

As a mound building species, digging is an intrinsic behavior of the red imported fire ants, Solenopsis invicta Buren. In this study, digging behavior of S. invicta was studied using sand as a digging substrate. When the group is small, grouped ants often had a significantly higher digging amount per individual than an ant in solitary, indicating that social facilitation occurred among ants. However, with ant numbers increased further, the digging amount per ant decreased, indicating digging inhibition took place. Ants preferentially dug the sand treated with worker body extracts and more ants were found in the treatment at the end of experiment. The body extract significantly increased the percentage of ants that exhibited digging behavior. These results indicate that chemical cues may play a role in social facilitation of digging behavior in red imported fire ants; however, these data can't explain the social inhibition observed in this experiment. The mechanisms behind the social facilitation, social inhibition and their transition require further investigation. This article is protected by copyright. All rights reserved.