Modelling the time-temperature relationship in cold injury and effect of high-temperature interruptions on survival in a chill-sensitive collembolan

1. Temperature- and time-dependent mortalities were studied and modelled in insects exposed in regimes with constant and alternating temperatures. In these experiments, freezing was not a cause of death. 2. Survival rates at a range of constant low temperatures (-5 to + 1 degree s C) and for different exposure periods (1-14 days) were measured in the su mmer acclimated springtail Orchesella cincta. 3. Daily interruptions of the cold exposure with short intervals at high te mperature reduced mortality or slowed the increase of mortality. This effec t was stronger at higher temperature (19 vs 5 and 12 degrees C) and increas ed with the duration of the interruption (0.25-2 h). 4. The injury was reversible when the cold exposure was limited to 2 days. 5. Survival in desiccated animals (14% water loss) was reduced. 6. It is suggested that the mortality of summer acclimated springtails is c aused by a complex metabolic disorder and membrane changes at low temperatu res.