specialization does not predict individual efficiency in an ant专业化不预测单个蚂蚁的效率.pdfVIP

PLoS BIOLOGY Specialization Does Not Predict Individual Efficiency in an Ant Anna Dornhaus1,2* 1 Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America, 2 School of Biological Sciences, University of Bristol, Bristol, United Kingdom The ecological success of social insects is often attributed to an increase in efficiency achieved through division of labor between workers in a colony. Much research has therefore focused on the mechanism by which a division of labor is implemented, i.e., on how tasks are allocated to workers. However, the important assumption that specialists are indeed more efficient at their work than generalist individuals—the ‘‘Jack-of-all-trades is master of none’’ hypothesis— has rarely been tested. Here, I quantify worker efficiency, measured as work completed per time, in four different tasks in the ant Temnothorax albipennis: honey and protein foraging, collection of nest-building material, and brood transports in a colony emigration. I show that individual efficiency is not predicted by how specialized workers were on the respective task. Worker efficiency is also not consistently predicted by that worker’s overall activity or delay to begin the task. Even when only the worker’s rank relative to nestmates in the same colony was used, specialization did not predict efficiency in three out of the four tasks, and more specialized workers actually performed worse than others in the fourth task (collection of sand grains). I also show that the above relationships, as well as median individual efficiency, do not change with colony size. My results demonstrate that in an ant species without morphologically differentiated