Study system. A) Geographical distribution of the species used in the experiments and B) phylogenetic relationships among them (modified from ref. ). Yellow background areas in the map, distribution of the limestone. Coloured circles, caves known to have the species; with a star, the cave from which the studied specimens were collected (M. infernus and T. arcticollis are only known from a reduced number of caves in close proximity, and their ranges are represented by a single circle). Numbers in the nodes, millions of years before present. Photo habitus, Troglocharinus ferreri.