The influence of nest architecture on colony organization in the ant Temnothorax rugatulus
Gregory T. Chism, Gregory T. Chism , Kerry A. Marquardt , Anna R. Dornhaus
Graduate Interdisciplinary Program in Entomology and Insect Science, The University of Arizona, Tucson, AZ, USA; Graduate Interdisciplinary Program in Entomology and Insect Science, The University of Arizona, Tucson, AZ, USA ; Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, USA ; Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, USA
Nest architecture in ants is an example of an extended phenotype, present across many social insect taxa. ‘Extended phenotypes’ are organism traits that extend into the environment: for example, in social insects, the nest, built by the colony, then can serve as a mechanism for microclimate regulation. Much attention has been given how the organism’s behavior shapes the extended phenotype, while the potential feedback from the phenotype (e.g. nest architecture) onto the colony’s behavior has been largely unexplored. The ant Temnothorax rugatulus provides an ideal model system to investigate the effects of nest architecture on colony organization, thus providing insight into the interactions between extended phenotypes and behavioral traits. We tested the hypotheses that (i) nest architecture affects worker and brood spatial distribution, in particular (ii) that nest architecture would determine extent and distribution of spatial fidelity zones (‘micro-territories’) of workers in the nest, and thus affect worker task choices and division of labor; and that (iii) nest architectures promote different queen movement patterns. Besides investigating the feedback between nest architecture and colony organization, our results provide insights into mechanisms of task allocation (worker task choices), since the spatial distributions of workers and brood affect how often different workers are likely to encounter task stimuli (e.g. brood). Our results illuminate the direct proximal influences of the extended phenotype on division of labor in social insects.