Cooperation and conflicts are hallmarks of insect societies. While cooperation of individuals is the main driver of the ecological success of social insects, colonies are always threatened by invasion of exploiters. Indeed, previously we reported that Kihoku population of the parthenogenetic ant, Pristomyrmex punctatus, is invaded by mutant“cheaters". We extend our scope concerning this system to the evolution-ecology feedback. In this recently rising subject, however, social behavior such as altruism and cheating have not been well focused. We compared the ant community structure of 8 sites where P. punctatus cheaters exist with that of 8 sites containing no P. punctatus cheater. This is a preliminary study to empirically test two alternative possibilities. Cheating by social cancers leads to the regulation of the population density of P. punctatus to a lower level, which makes this species less competitive and permits the domination of or coexistence with other ant species. Conversely, community-level dynamics allow the population of P. punctatus to increase a high level that makes cheaters sustainable. If the latter effect were to prove more important, it would challenge the view that intra-population dynamics is the main driver of evolution.