The mound of the free-living F. polyctena colony built on the outlet of the ventilation pipe; the source of the bunker ‘colony’. Photo taken on 24.07.2015 (Wojciech Stephan).

  Part of: Czechowski W, Rutkowski T, Stephan W, Vepsäläinen K (2016) Living beyond the limits of survival: wood ants trapped in a gigantic pitfall. Journal of Hymenoptera Research 51: 227-239.