MACROPTERY IN ALTITUDINAL SPECIALISTS VERSUS BRACHYPTERY IN GENERALISTS - A PARADOX OF ALPINE SCANDINAVIAN CARABID BEETLES (COLEOPTERA, CARABIDAE)

Non-riparian alpine carabid beetle assemblages in Scandinavia are usua lly dominated by a set of seventeen species. Five of these species are more or less restricted to the alpine and subalpine regions (altitudi nal specialists), whereas the remaining twelve species are widespread also in lowland (altitudinal generalists). Flight-wing length differs between these two groups of species, i.e. all altitudinal specialists are macropterous, whereas seven of the generalists are brachypterous o r dimorphic with the brachypterous morph strongly dominating. Generali sts abundant in lowland forests are all brachypterous, whereas the mac ropterous species in lowland are confined to open, dry habitats. The d ominance of macroptery among altitudinal specialists is paradoxical as the alpine environment generally is supposed to select for brachypter y, and the specialists should be better adapted to their habitat than the generalists are. Available subfossil evidence suggests that the sp ecialist species reached the Scandinavian Mountain Range from a contin ental refugium south of the ice sheet. The macroptery of the specialis ts can be explained by the relative recentness of the last glaciation and the lower dispersal power of the brachypterous or apterous tundra species that have not been able to colonize Scandinavia from their gla cial refugia. The time available for colonization of generalist specie s following deglaciation was probably much longer than for specialists , and consequently brachypterous species were successful. Wing dimorph ism as a tool for reconstructing faunal history is discussed.