Feeding and growth in the Antarctic collembolan Cryptopygus antarcticus

Variations in the rate of moulting and of faecal pellet production by Cryptopygus antarcticus (Willem), collected from Signy Island in the maritime Antarctic, were measured over temperatures of 0° to 20°C. Over the range 5° to 15°C total faecal pellet production between moults was similar; at 0°C there was little feeding activity, whilst mortality was high at 20°C. The temperature of maximum moulting frequency is lower for this species than for temperate Isotomidae, suggesting cold adaptation of its moulting behaviour. Growth of individual specimens at 10°C was measured from mandibles recovered from shed exuviae after each moult, using a linear relationship between body length and mandible length. At a body length of 1040-1134 μm, individuals either increased or decreased in size at subsequent moults. The results suggest that the minimum age of the largest specimens of Cryptopygus on Signy Island is probably 3-7 yr