The medium is the message: a review of Ant Encounters: Interaction Networks and Colony Behavior, by Deborah M. Gordon

When the cultural media critic Marshall McLuhan wrote these famous words in 1964, he may not have realized they might also apply to the organization of ants as Deborah Gordon has come to understand them. Ten years ago, Gordon wrote Ants At Work: How an Insect Society is Organized (2000), a short book that gave general readers a rich, first-hand account of her work on the behavior and ecology of the red harvester ant, Pogonomyrmex barbatus, which she has studied in the Arizona desert for over 25 years. Her new book, Ant Encounters: Interactions Networks and Colony Behavior (2010), is of similar length and format, and picks up the trail of the previous one, exploring ant colonies as complex systems whose behavior as a unified whole emerges from the self-organizing activity of its parts. Ant Encounters is both a reiteration and extension of Gordon’s thesis that the key to understanding the behavior of an ant colony as a collective entity lies in the particular pattern of local interactions among individuals and the tasks they are performing at a given time. The hypothesis seeks to explain behavior of ant colonies in a generalized sense, with red harvester ants (affectionately known as ‘‘Pogos’’ to ant biologists) as the model system. Gordon’s detailed research on task allocation within Pogo colonies and the behavioral dynamics between them is unique in the field because of her many years of continuous observation tracking the same colonies. Given this empirical depth, her research program has contributed novel insights into our understanding of colony growth, lifecycle, and the means by which ants manage to coordinate on the level of the ‘‘superorganism,’’ despite a lack of any centralized control. A key conclusion that Gordon draws from both empirical observations and computer models is that change in the size of a colony (in terms of the number of individual workers) is essentially a change in the size of an adaptive network, with each worker ant functioning as a participatory and interactive node. Changes in colony size bring about changes to the rate and pattern of local interactions, and this in turn fundamentally alters the behavior of an ant colony and its responsiveness to its environment. The particular focus on rate and pattern of interaction is a fundamental and crucial aspect of Gordon’s hypothesis: ‘‘The pattern of interaction itself, rather than any signal transferred, acts as the message. What matters is not what one ant tells another when they meet, but simply that they meet’’ (pp. 47–48). The medium, alas, is the message. Ants may ‘‘tell’’ each other something via pheromones, but the idea is that these act as auxiliary cues for contextualizing the fundamental message that is embedded within the rate and pattern of the ant-ant interaction itself as well as the configuration of connectivity these collective interactions subsequently generate colony-wide. It is this quality of networked interactions that Gordon believes links ant colony behavior to a range of other complex and self organizing systems like brains, immune systems, and the internetFall of which are distributed, noisy, and highly responsive wholes composed of relatively simple parts. Gordon makes clear that she believes this perspective on ant organization contrasts sharply with the extensive body of research that employs the concept of specialized ‘‘castes’’ that EVOLUTION & DEVELOPMENT 12:5, 534–536 (2010)