Composition élémentaire (C,H, N) de Sphaeroma serratum et S. hookeri (Crustacea: Isopoda)

The elementary composition (C, H, N) of Sphaeroma serratum and Sphaeroma hookeri has been studied in different natural populations and also in individuals maintained in laboratory cultures. Changes in elementary composition have been observed in the natural communities. Laboratory experiments demonstrated that food may influence the isopod's chemical composition. These results provide an explanation fom the intraspecific differences which appear to characterize natural populations.