Ants trapped for years in an old bunker; survival by cannibalism and eventual escape

Successful evacuation of a peculiar ‘colony’ of the wood ant Formica polyctena Först., for years trapped within an old bunker previously used for storing nuclear weapons (see Czechowski et al. 2016), is reported. Using an experimentally installed boardwalk, the imprisoned ants managed to get through the ventilation pipe to their maternal nest on the top of the bunker. In our previous report, we left open the question of how the ‘colony’ could survive seemingly without food. Here we show that the ‘colony’ in the bunker survived and grew thanks to an influx of workers from the source nest above the bunker and mass consumption of corpses of the imprisoned nestmates.