Lasius (Acanthomyops) species have long been suspected as temporary social parasites of other Lasius ants despite a lack of evidence for this in all but two of the 16 species. Wing (1968) proposed severaly hypotheses for founding stage of Lasius (Acanthomyops) including various modes of social parasitism as well as independent foundation. In 2005 and 2006 I studied the founding stage of Lasius (Acanthomyops) interjectus, claviger, and latipes in the field and laboratory. Here I report the results of introduction experiments, forced associations of gynes, and choice experiments in which gynes were allowed to remain solitary or join other gynes.