Comparing oxygen uptake rates of driftwood and wrack generalist talitrid amphipods

Rates of oxygen consumption in seawater standardized for size (mass or body length) were compared for a representative supralittoral, wrack generalist talitrid – <i>Platorchestia platensis</i> and a representative driftwood, specialist talitrid – <i>Macarorchestia remyi</i>. Oxygen consumption in seawater was significantly less in <i>M. remyi</i>. This confirms the view that a reduced standard metabolic rate, and consequent reduction in growth rate and final size achieved, was an important physiological mechanism involved in dwarfism and adaptation to driftwood in <i>M. remyi</i>. Reduced standard metabolic rate in driftwood specialist talitrids is contrary to the metabolic theory of ecology.