A contribution to the geologic history of bark beetles

Insect borings, unique in the fossil record, were found in fossil wood from a thin lignite seam of lowermost Cretaceous age, exposed in cliffs of the southwestern shore of the Isle of Bornholm (Denmark). The find consists of six thin, roughly parallel, short passages connected with a remnant of a long straight tunnel running along a mechanically-induced fissure just below the wood surface. This find is not fully analogous with the presently most common feeding insect borings as the passages are situated in an oblique fissure of the wood sample (instead of the usual position below the bark). Nevertheless, the best modern analogues of the borings found in Bornholm still come from the insect forestry pests such as the Scolytidae (bark beetles). The find shows that ecological predecessors of bark beetles probably first inhabited random mechanic cracks; later, they occupied the most devastating niche at the boundary between the bark and the wood. More in the paper (Journal Ichnos).