SURFACTANTS IN THE GUT FLUIDS OF PORCELLIO SCABER (ISOPODA, ONISCIDEA), AND THEIR INTERACTIONS WITH PHENOLICS

Fluids from the gut lumen of Porcellio scaber showed significantly red uced surface tension compared to a buffer solution. Tests with several dilutions indicated that the concentration of the surface active subs tances (surfactants) was about 80-fold higher than the 'critical micel le concentration'. Phenolics, e.g. gallotannins, when ingested in the diet increased the surface tension of the gut fluid, indicating reduce d concentrations of free surfactants. The significance of gut surfacta nts in P. scaber, their role in digestive processes, and their interac tion with tannins in this saprophagous soil arthropod are discussed. ( C) 1997 Elsevier Science Ltd. All rights reserved.