Metabolic Adaptations to Seasonal Changes in Humidity and Temperature in Litter-Inhabiting Collembola

Emptying of the gut in Orchesella cincta (L.) (Collembola) is considered as an important phenomenon in preventing water loss during drought in summer and freezing during low temperatures in winter. The effects of the resulting starvation have been studied in the laboratory. Starvation results in a strong metabolc suppression and in an arrest of growth and reproduction. These effects were found to be greater in a spring population than in an autumn one. Further, the weight-specific oxygen consumption (metabolic rate) at 15'C of fed adult spring animals (392.9 ? 13.1 [1 02 g-l h-1) was significantly higher than that of fed autumn animals (314.6 ? 11.1 1 02 g' h-1), and in the autumn animals growth was retarded and reproduction arrested. It is concluded that the assimilated energy is partitioned differently in the spring and autumn animals; in which production and maintenance respectively are stressed. The adaptive response to drought in summer is interpreted as a quiescence, to low temperatures in winter as a diapause.