Where is the nest? A peculiar mode of synanthropic nesting of Lasius niger (L.) (Hymenoptera: Formicidae)

Lasius niger (L.) is a common ant species with strong synanthropic tendencies. It commonly occurs in various anthropogenic environments, including the immediate vicinity of human habitations. In Europe, L. niger is one of the most numerous species in urban habitats; its gynes, fertilised during their nuptial flights, sometimes fall onto balconies in residential buildings, where they are able to give rise to new colonies. Described and discussed here is the functioning of such a L. niger colony and its unusual way of nesting under the Styrofoam insulation of a concrete wall, i.e. in conditions very much unlike those in nests typical of the species.