Moisture and temperature dependent changes in the cuticular permeability of the antarctic springtail Parisotoma octooculata (Willem)

This paper provides an introduction to the literature on the drying of porous solids and the relevance of these drying theories to the drying of Collembola in general, and hygrophilic Collembola in particular is discussed. The rate of drying of Parisotoma octooculata was highly dependent on both moisture content and temperature. Increasing the external drying temperature from 5 to 20°C, increased the cuticular conductance or permeability to water vapour from 15.8 to 72.0 mm/min; a change of 56.2 mm/min. Decreasing the moisture content from 3.5 to 2.0 g/g (grammes of water per gramme desiccated weight), whilst simultaneously increasing the temperature from 5 to 20°C, retarded the rate of transpiration. Moisture and temperature acted antagonistically to retard and promote transpiration in equal measure. The cuticular conductances to water vapour, of 16 species of Collembola from a wide range of habitats, were calculated using equivalent units, and then compared. There was a strong correlation between permeability and habitat type: the drier the habitat the lower the conductance value