Lipofuscin, body carbon and respiration rates were measured in Hyas araneus from hatching to metamorphosis. Excitation/emission spectra of both the chloroform and the methanol/aqueous phase showed one distinct fluorescence peak in the chloroform (410-415 nm emission/340-350 nm excitation) and the methanol/aqueous phase (405/350 nm) of zoea I (directly after hatching) and megalopa (0 and 24 days old). Individual lipofuscin concentrations increased continuously during zoea I and halfway through zoea II, but remained constant through the entire megalopa despite high metabolic activity in this stage. Individual lipofuscin concentrations were positively correlated with body carbon and carbonspecific lipofuscin was negatively correlated. Moulting cause considerable loss of lipofuscin.