SEASONAL LIPID CONTENTS OF ANTARCTIC MICROARTHROPODS

A technique for the accurate determination of lipid content of very small quantities of biological tissue was applied to two Antarctic oribatid mites, Alaskozetes antarcticus and Halozetes belgicae, and a collembolan, Cryptopygus antarcticus. Analysis of monthly samples of the three species, collected between November 1989 and March 1991, revealed little evidence of any seasonal pattern of lipid deposition or use. Male Alaskozetes were the only exception, showing very low lipid levels for a short period of the austral summer, followed by rapid deposition before the onset of winter. Mean lipid contents of the three species over the study period were 10-15% of mean dry weight. There was evidence of a seasonal pattern of egg formation and oviposition in both Alaskozetes and Halozetes, but this was not reflected in the observed lipid levels. Feeding activity was mostly restricted to the summer months (November-March); a temporary resumption of feeding in winter (late August 1990) was followed by an increase in lipid content in both sexes of Alaskozetes.