Measuring competition coefficients in an ant community: Implications for intraspecific adaptation load

Understanding the stable coexistence of species despite resource competition has been a central topic in ecology. Ant communities are particularly enigmatic as various species coexist despite resource overlap. Community ecology theory predicts stable species coexistence when intraspecific competition is stronger than interspecific competition, but due to their perennial and underground life, competition coefficients of ants have never been rigorously measured in the field. We tackled this problem by studying Diacamma cf. indicum, which allows for non-invasive mark–recapture of whole colonies. Several ant species coexisted at the study site where Diacamma was most abundant, and baiting experiments and stable isotope analyses suggested overlapping food niches. Consistently, per-worker brood production of Diacamma colonies was significantly negatively correlated with con- and heterospecific worker densities within the foraging area, suggesting exploitative competition among the ants. In te..., , , # Measuring competition coefficients in an ant community: Implications for intraspecific adaptation load [https://doi.org/10.5061/dryad.8pk0p2nwk](https://doi.org/10.5061/dryad.8pk0p2nwk) File: File_1-6_in_Uematsu_et_al..zip Here, you can access all the data used in this study. To measure the intra- and interspecific competition coefficients of *Diacamma* cf. *indicum* in the field, we examined the relationship between the intra-colony demography of *Diacamma* and the local ant community structure using the following methods. Intact colonies of *Diacamma* were collected using the bamboo-traps. After carefully examining their colony composition (number of workers, brood weight, etc.), all workers were individually marked, and the colonies (nested in traps) were released intact at random locations in the study site. After one week, those colonies were recaptured, and any changes in colony composition were examined. In addition, local ant communities within a 5-m radius of the release...,