Box 9 II The beetle Rhysodes sulcatus

Rhysodes sulcatcus


A case of a species occupying a very particular habitat, and whose history is known to some extent, is offered by the beetle Rhysodes sulcatus. This beetle lives beneath the bark of large, standing, dead trees that are well-rotted, in circumstances where an appropriate microclimate is provided by surrounding forest. This habitat is now very scarce in today's Europe, and over much of the continent potential sites for R. sulcatus do not exist. However, it has been observed in most places where the habitat does exist that the beetle does not. Is this because it has disappeared from these parts of Europe, or because it never occurred there in the first place? It is now known from fragments collected in dated archaeological contexts (Buckland and Dinnin, 1993) that 3000 years ago this beetle ranged as far west in Europe as southern England, but that it had disappeared there by the time entomologists became active. At the beginning of the nineteenth century R. sulcatus was still found in southern Scandinavia, but has subsequently disappeared there also. At the beginning of the 20th century this beetle was recorded in Central Europe, but since then has not been found. Since 1950, the species has only been found in Europe in a few isolated colonies in the Pyrenees and mountainous parts of northern Greece. This history is illustrated in Map 9.25. The implication is that this beetle has disappeared along with Europe's natural forest cover. Its European range has shrunk from what was probably a pan-European coverage in prehistory to a few colonies today. These colonies are now so remote from one another that genetically and in every other respect they are now entirely out of contact, being separated by vast tracts of land where habitats for the species do not exist.


Map 9.25 - Disappearance history of Rhysodes sulcatus

Source: M Speight, personal communication