Effect of diet on oxygen uptake rate in the talitrid amphipod Platorchestia platensis

ABSTRACT The primary ecotope for Platorchestia platensis is supralittoral wrack, but occasionally this species may be found living in, and feeding on, rotting driftwood as a secondary ecotope. Lower oxygen uptake rates were measured for driftwood-fed compared with wrack-fed P. platensis. The null hypothesis that the metabolic rate in P. platensis would remain unchanged after reversing the diet from driftwood to wrack was rejected. Diet reversal experiments demonstrated that the oxygen consumption rates of P. platensis were reversible and gradually attained. This is consistent with the change of diet from wrack to driftwood, or vice versa, causing physiological changes involving oxygen consumption in P. platensis, which are described as acclimation rather than adaptation.