THE EFFECT OF ENCHYTRAEID FECES AND MUCUS ON THE FOOD CHOICE OF PORCELLIO SCABER (ISOPODA)

Three series of food preference experiments with the isopod Porcellio scaber were carried out: (1) maple leaf discs (Acer pseudoplatanus) im mediately after exposition to the excrements and mucus of Enchytraeus albidus (Clitellata: Enchytraeidae), (2) leaf discs after exposition a nd subsequent incubation for one week, and (3) leaf discs after exposi tion and incubation for two weeks, were offered as food, with similar, untreated leaves serving as a control each time. A highly significant preference for ''worm-exposed'' leaves by P. scaber was shown in expe riment (2). Microbial respiration and numbers of colony-forming units - both bacterial and fungal - were highest on maple leaves immediately after exposition to enchytraeid products and thereafter decreased rap idly. Compared with untreated leaves, the C:N-ratio was considerably l ower in leaves with worm contact and one week incubation.