Survival and water loss in some Antarctic arthropods

Seven species of Antarctic micro-arthropods (4 mites and 3 collembolans) were examined to determine their resistance to dehydration and their survival under dry conditions. Water loss at r.h. 5% at temperatures in the range −10 to 45°C was measured gravimetrically using a recording micro-balance. Survival of samples of mites was monitored after exposure to r.h. 5% and temperatures in the range 0–20°C. Rates of water loss ranged from 0 to about 30% fresh weight h−1 depending on temperature and species. The 3 Collembola were least resistant and the 2 oribatid mites were most resistant to dehydration under the experimental conditions. The optimal survival temperature of the mite Alaskozetes antarcticus was around 10°C under 5% r.h.; there were no significant differences in rate of water loss between temperatures. The results are discussed in terms of possible control mechanisms and the type of habitat occupied by each species.