Temperature effects on lipid composition of the earthworms Lumbricus rubellus and Eisenia nordenskioeldi

Two earthworm species, the freeze-intolerant Lumbricus rubellus (Hoffmeister) and the freeze-tolerant Eisenia nordenskioeldi (Eisen), were compared with respect to the effects of temperature on lipid composition. The animals were incubated at either 0°C or 20°C for 28 days, and then analyzed for the composition of free and ester-linked long-chain fatty acids, as well as other lipids with similar properties. Inter-species differences dominated the patterns of lipid composition, and the two species responded similarly to incubation temperature with respect to changes in lipid composition. In particular, polyunsaturated fatty acids were present in higher concentrations at 0°C, while straight-chain saturated fatty acids were more common at 20°C. The results did not implicate specialized lipid adjustments in the freeze-tolerance of E. nordenskioeldi.