Further studies of the army-ant behavior pattern. Mass organization in the swarm-raiders.

Abstract

The paper is a study of the nature of the individual behavior pattern in relation to the organization of group behavior in the swarm raid of the army-ant. Thorough descriptions of the swarm raid are given. The following explanations of the various characteristics of the raid are advanced: The raid is initiated through photokinesis, first occurring as a radical expansion around the bivouac and then assuming direction-alized advances. The growth and characteristic form of the raid is dependent mainly upon pressure-that is the push of the ants behind the vanguards. Drainage-the tendency for the ants in the center and rear to flow into open spots resulting from the movements of ants in the outlying edges-is another means of transmission of mass change; Major changes in the direction of swarm advance are to be referred to environmental factors. Every ant makes essentially the same contr. to the raid under similar conditions, the leadership of the advance being a function of collective behavior. Different aspects of the raid such as "pseudopodic columns." "flanking movements," "the fan" are described.