[Adaptations of Pterostichus nigrita F. (Col., Carab.) to subarctic conditions].

Two physiological races of the carabid beetle, Pterostichus nigrita, are compared. The larvae from the northern Scandinavian population (polar circle) develop faster in all temperature regimens, have a reduced mortality in lower temperatures and an increased growth rate in high temperatures compared with the central European beetles (Cologne). Thus they are able to survive sudden cold spells and during optimal temperatures can compensate for periods of reduced development.In females sexual maturity is induced by short-day photoperiods followed by long-day photoperiods (previtellogenesis and vitellogenesis, respectively). Males can mature in short-days alone (formation of spermatozeugma). All short-day dependent processes of the subarctic beetles are still possible in far longer photoperiods. The critical day-length, however, for vitellogenesis is only slightly changed.The ecological significance of these physiological adaptations is discussed.