Physics Colloquium: An ant of few words: group communication with limited vocabulary

Abstract:

Biological individuals often interact to form cooperative societies that have functional advantages. How the specifics of these interactions constrain collective performance is not well understood. In this context, we study how desert ants inform each other about the presence of food. We use automated tracking to generate a large data-base of ant trajectories and interactions that provides us with sufficient statistics to empirically estimate the efficiency of their communication. This is done, quantitatively, by calculating the information theoretical channel capacity of the ants' pairwise interactions. We find that this channel is noisy to a degree that makes it difficult for ants to tell between a recruiter reporting about food and a random collision within the dark nest environment. To distinguish these ambiguous signals the colony must therefore perform error-correcting on the level of the group. We demonstrate that the ants accomplish this by exhibiting strict control of when to transmit a message and when to respond to received information. This control leads a collective process that couples negative and positive feedbacks and ensures reliable colony performance. Thus, the ants need no language, but just one aptly used "word" pronounced with conviction inside a noisy environment.

Seminar Organisers: Dr. Tomer Volansky, Dr. Dovi Poznanski