Ytong ant nests

Ytong is just a brand name. The material itself is called aerated concrete. Due to its water-storing property, the material is well suited for keeping ants. Many types of earth-nest digging from dry and moist habitats can be kept in it. The nest has prefabricated natural chambers and passages so that the ants can move in directly.

The sizes of the Ytong nests (M, L) do not refer to the external dimensions, but to the distance between the inside of the nest or the nest entrances and connection holes (adapted to the size of different species of ants).
M = 10mm for medium types such as Lasius sp. and Formica sp.
L = 20mm for large species such as Camponotus sp.