A comparison of mark-release-recapture methods for estimating colony size in the wood ant Formica lugubris

摘要

Colony size can be considered the analogue of the body size of a superorganism. Just as body size is important to the physiology of an individual animal, colony size correlates with the life-history and ecology of social insects. Although nest excavation and counting all individuals is the most accurate method for estimating colony size (or nest size), it has the major drawback of being destructive. Alternatively, mark-release-recapture (MRR) can be used repeatedly to measure the size of the same colony or nest. We compared the accuracy and feasibility of four MRR methods and a Mound-Volume method with complete counts from nest excavation for estimating the nest size of F. lugubris, a mound-building wood ant of the Formica rufa group, during the early spring in Scotland. We found that our After-Disturbing method, in which we performed marking and recapturing after gentle disturbance to the top of nest mound, has the best balance between accuracy, non-destructiveness, and time required. We also found that mound volume can be an index of ant nest size under certain conditions. Both non-destructive methods can be used on the same colony or nest repeatedly to monitor nest dynamics.