Vibrational Communication Outside and Inside the Nest in Leaf-Cutting Ants

Abstract

Ants live in complex societies that organize their activities, as all animal societies, mostly by means of communication. While chemical communication via pheromones is ubiquitous in ants, increasing evidence points at the use of stridulatory vibrations not only as modulators of chemical communication signals but also as releasers of context-specific behaviors. Leaf-cutting ants, particularly those of the genus Atta, have extensively been investigated concerning both physiological and behavioral aspects of their vibrational communication, and they therefore provide the most comprehensive example of the use of vibrational signals as organizers of social behavior in ants. In this chapter, I summarize pioneer, early studies on signal production, response sensitivity thresholds, and function of stridulation in Atta leaf-cutting ants. I then follow with more recent laboratory and field investigations highlighting different contexts, both outside and inside the nest, in which leaf-cutting ants employ mechanical communication to coordinate their behaviors. These encompass cutting behavior and recruitment of nestmates, leaf transport, leaf processing inside the nest, nest excavation, and underground waste disposal. It will be argued that the response to stridulatory signals in leaf-cutting ants, despite their elementary and unitary character, strongly depends on the social context in which the receivers are situated.