ASU SoLS Faculty: Stephen Pratt

Collective Animal Behavior, Bioinformatics

I study how the complex behavior of animal societies emerges from the interactions of group members, despite the absence of any well-informed central controller. I focus particularly on the rich examples found in ants, bees, and other social insects. The appearance of order at one scale from purely local interactions at a lower scale is a general theme of modern biology, seen in genetic, neural, social, and ecological networks. My goal is to understand this process in systems whose middle rank between organisms and populations makes them especially tractable. My approach is to identify the behavioral rules, cues, and signals used by individuals, and to experimentally test hypotheses of how these parts interact to yield colony-level behavior. Although I focus on mechanisms, I also aim to link individual behavior to fitness benefits at the colony level. I work largely on two model systems: 1) decision-making during colony emigration by ants of the genus Temnothorax and 2) adaptive resource allocation during colony growth by honey bees.

Because intuition alone cannot take in this complexity, I rely extensively on mathematical and computational approaches. These include dynamic optimization models, statistical analyses of large data sets, and simulations of collective colony behavior. I am also collaborating on computational analyses of yeast genomic data, aimed at mapping and interpreting variation in nucleotide sequence at a genome-wide scale. In the future these and related approaches can contribute to understanding the collective behavior of honey bees. As the first social insect to have its genome completely sequenced, the honey bee represents a rich opportunity for genetic studies of sociality.

Selected Publications

Balch, T., Dellaert, F., Feldman, A., Guillory, A., Isbell, C., Khan, Z., Pratt, S.C., Stein, A., and Wilde, H. How A.I. and multi-robot systems research will accelerate our understanding of social animal behavior. Proceedings of the IEEE, in press.

Gresham, D., Ruderfer, D. M., Pratt, S.C., Schacherer, J., Dunham, M., Botstein, D. and Kruglyak, L. (2006) Genome-wide mapping of polymorphisms at nucleotide resolution with a single DNA microarray. Science 311: 1932-1936.

Pratt, S.C., Sumpter, D.J.T., Mallon, E.B. and Franks, N.R. (2005) An agent-based model of collective nest choice by the ant Temnothorax albipennis. Animal Behaviour 70: 1023-1036.

Pratt, S.C. (2005) Quorum sensing by encounter rates in the ant Temnothorax albipennis. Behavioral Ecology 16: 488-496.

Pratt, S.C. (2004) Collective control of the timing and type of comb construction by honey bees (Apis mellifera). Apidologie 35: 193-205.

Sumpter, D.J.T. and Pratt, S.C. (2003) A modeling framework for understanding social insect foraging. Behavioral Ecology and Sociobiology 53: 131-144.

Pratt, S.C., Mallon, E.B., Sumpter, D.J.T., and Franks, N.R. (2002) Quorum sensing, recruitment, and collective decision-making during colony emigration by the ant Leptothorax albipennis. Behavioral Ecology and Sociobiology 52: 117-127.

Pratt, S.C., Brooks, S.E. and Franks, N.R. (2001) The use of edges in visual navigation by the ant Leptothorax albipennis. Ethology 107: 1125-1136.

Pratt, S.C., Daly, M.J. and Kruglyak, L. (2000) Exact multipoint quantitative-trait linkage analysis in pedigrees by variance components. American Journal of Human Genetics 66: 1153-1157.

Pratt, S.C. (1999) Optimal timing of comb construction by honey bee colonies: a dynamic programming model and experimental tests. Behavioral Ecology and Sociobiology 46: 30-42.

Pratt, S.C. (1998) Decentralized control of drone comb construction in honey bee colonies. Behavioral Ecology and Sociobiology 42: 193-205.