Anpassungen des Laufkäfers Pterostichus Nigrita F. (Coleoptera, Carabidae) an Subarktische Bedingungen

Abstract

Two populations of the carabid beetle Pterostichus nigrita are compared: one from the region of Cologne (Germany), the second from the polar circle (North Sweden). According to the subarctic environment the northern population shows some physiological adaptations which can be considered to be essential for survival in that geographic region.

The larval development is accelerated in all temperature regimen used compared with the German population. Sufficent development can even take place at low and high temperatures.

Sexual development in the adults is stimulated by photoperiods. The critical photoperiods inducing previtellogenesis in females and total maturation of males are shifted into long days for about 4 hours. This observation is well in concert with the tendency of critical daylength to increase from 1,0 to 1,5 hours for every 5° increase in the latitude of the insects population’s origin.

All experimental datas classify the northern population as a physiological race.