Intestinal Microbiota of Terrestrial Isopods

Isopods are a cosmopolitan group of crustaceans, which inhabit marine environments ranging from deep-sea to intertidal areas, surface and underground freshwaters and terrestrial environments fromhigh humidity to dry habitats, including deserts. More than one third of the described isopodan species (approximately 9000) belong to the terrestrial Oniscidea or woodlice (slaters, sowbugs and pillbugs; Schamlfuss 2003). The phylogeny and systematics of Oniscidea were analysed and presented by several authors (Schmalfuss 1989; Erhard 1998; Tabacaru and Danielopol 1999). In general, Oniscidea are assigned to five sections, namely Diplocheta, Tylida, Microcheta, Synocheta andCrinocheta, with 33 families altogether (Erhard 1998). Amphibious species of the family Ligiidae (slaters) and members of Mesoniscidae represent only approximately 50 of the described species, the rest belonging to the higher oniscideans,mostly to troglobiontic Synocheta and “truly terrestrial” Crinocheta. Terrestrial isopods are effective herbivorous scavengers feedingpredominantly on decayed plant material, fungi and algae, thus participating in decomposition and cycling of energy and organic matter in the terrestrial environments (Hopkin 1991; Zimmer and Topp 1997). Due to their significant ecological role and their ability to survive in polluted environments, a substantial amount of research was focused on these organisms, and as a result a comprehensive knowledge accumulated on their biology. Species like Porcellio scaber and Oniscus asellus, for example, are among the most studied organisms in terrestrial ecophysiology and ecotoxicology (Hopkin 1989; Drobne 1997). Terrestrial isopods have diverse feeding strategies including coprophagy and occasional cannibalism. The nutritional importance and significance of coprophagy in the field was not demonstrated