SUPPLEMENTARY FOOD IN THE DIET OF THE TERRESTRIAL ISOPOD PORCELLIO SCABER LATR. (ISOPODA: ONISCIDEA)

ABSTRACT

In laboratory experiments with Porcellio scaber, the primary food (Norway maple litter) was supplemented with artificial (gelatin, bran) or natural (feces) food sources. Total food consumption was similar, whereas the proportion of different food sources in the isopods' diet, as well as assimilation efficiency, varied greatly. Isopods grew best when the supplementary food was bran and gelatin, and their survival rate was also high on the bran and gelatin diet. The chemical composition of the (secondary) feces produced during the experiments also differed significantly between treatments. Nitrogen content and carbon to nitrogen ratio in secondary feces were lowest in the gelatin-supplemented regime. In the present experiments, feces did not increase fitness correlates as much as the artificial supplementary food, which may be partly due to the use of freshly produced dried feces which had not undergone microbial action.