The influence of temperature on locomotor activity was determined for the sub-Antarctic mites, Halozetes fulvus Engelbrecht and Podacarus auberti Grandjean. In both species walking was severely impaired at below-freezing temperatures. Above zero, locomotor activity rates increased with a rise in temperature over a wide temperature range (for example, this was 2-30°C for H. fulvus), and they showed a biologically normal level of sensitivity to change in temperature. All the calculated Q10 values for mean rates over 5° intervals varied between 1.3 and 2.9. The present data are compared with some rate functions of maritime and continental Antarctic micro-arthropods, and they confirm the relative enhancement of the physiological rate by a continental Antarctic mite. One explanation for the less temperature-sensitive rates in H. fulvus and P. auberti may be that they have relatively more time available for normal biological activity.