Hydroporus ferruginous (Dytiscidae): A subterranean water beetle recorded from Peak Cavern, Derbyshire, UK

Two new records of Hydroponis ferrugineus in Peak Cavern, Derbyshire, are reported at approximately 900m and 960m from the main cave entrance. Since the cave stream at this point is fed only by autogenic percolation water the records raise questions concerning the mode of colonisation, the ability of this species to complete its lifecycle in caves and the existence of a subterranean food web.