Meeting Abstract

15.4  Tuesday, Jan. 4  Metabolic and behavioral integration in social insect colonies WATERS, James S.*; FEWELL, Jennifer H.; HARRISON, Jon F.; Arizona State University; Arizona State University; Arizona State University james.waters@asu.edu

The hypometric scaling of metabolic rate with body size is among the most general patterns in biology. We investigated whether this pattern extends to physically independent eusocial systems by measuring the metabolic rates of whole functioning colonies of Pogonomyrmex californicus. Contrary to the predictions of an additive model, colony metabolic rate allometry resembled the pattern observed for individual organisms, scaling hypometrically with the 0.75-power of whole colony mass. This pattern could not be explained by scaling of individual ant size across colonies or by the effect of density on metabolic rate. While growth rates typically decrease in larger individuals, larger ant colonies exhibited higher growth rates and growth efficiencies. Isolated worker groups exhibited isometric metabolic rate scaling, suggesting that the social environment of the colony was critical to regulating individual patterns of metabolism and work output. The distribution of individual walking speeds became less uniform as colony size increased, suggesting that disparities in effort among individuals increased with colony size. It is possible that the fraction of relatively inactive ants explains a major component of metabolic hypometry. We compare these findings with the results of social network analysis which suggests that colonies exhibit patterns of localized interactions characteristic of regulatory networks. This work was supported by NSF IBN 0419704, NSF EAR 0746352, NSF 0446415 to JFH and NSF GRFP to JSW.