Notes on the ecology and physiology of the Antarctic oribatid mite Maudheimia wilsoni^*

* Publication No. Jl4 of the Norwegian Antarctic Research Expeditions 1976/77, 1978/79, 1984/85 and 1989/90.

Abstract

The oribatid mite Maudheimia wilsoni Dalenius was found to be numerous on the underside of stones at Jutulsessen (72°S, 3°E) in Dronning Maud Land, Antarctica. Daily temperature fluctuations of the microhabitat from as high as 19°C and to as low as – 17°C were observed during the austral summer. Optimal activity of the mites occurred at 10°C. Even in January the mean supercooling point of adult mites was as low as -30.8±4.7°C. Haemolymph osmolality ranged from 500 to 800mOsmol and thermal hystersis freezing points from -4.7 to -6.1°C. Adult mites had a mean water content of 43.6% and a water loss rate of 0.12 μgh^-1 at 15°C and 10% relative humidity.

Notes

* Publication No. Jl4 of the Norwegian Antarctic Research Expeditions 1976/77, 1978/79, 1984/85 and 1989/90.