Population Metabolism of the Terrestrial Isopod Philoscia Muscorum in a Dune Grassland Ecosystem

Abstract

The results of a laboratory investigation into the respiratory metabolism of P. muscorum (Scopoli) (Isopoda) are presented. Respiratory rate was significantly influenced by the body size, sex and breeding condition of the individuals and also by temperature and season. The experimental data were summarized in a multiple regression model. Using this model in conjunction with population sampling and field temperature data, the O2 consumption of a field population in a dune grassland ecosystem was estimated. Population metabolism varied from 6.98-13.98 KJ m-2 yr-1 over the period 1968-1973, most of the variation being attributable to changes in population density. The errors and limitations involved in using this method to estimate population metabolism are discussed and compared with those of other methods commonly used for extrapolating the results of laboratory energetics studies to field populations.