#steinlaus

Have you ever seen rocks or stone buildings peppered with numerous holes? You may have assumed these were the result of natural erosion, but many cases are in fact caused by a widespread yet rarely-seen animal.

[ Image above: extensive damage to an ornamental rock in Boston, Massachusetts, USA. (Source) ]

These holes are often the work of the stone louse (Petrophaga lorioti), a shy insect with chisel-like mandibles which chews its way through solid rock in a manner convergently similar to the gnawing of rodents. It feeds primarily on organic “biofilm” on stone surfaces, but also appears to derive some nutrition from the rock itself thanks to symbiotic lithotrophic microbes in its gut.

Originally native to Germany (where it is known as the “steinlaus”), it has spread across the globe in association with human settlements, and can be a particularly destructive pest in urban settings. Although only about 2.5cm long (1″), individual specimens have been observed to be capable of processing up to 28kg of stone (62lbs) in a single day.

die "Steinlaus"