Feeding of Scheloribates laevigatus (Acari : Oribatida) on different stadia of decomposing grass litter (Holcus lanatus)

The feeding of the panphytophagous mite Scheloribates laevigatus on litter of the abundant meadow grass Holcus lanatus was studied in laboratory exper iments. The micro-anatomy of the digestive tract and the isolation of fungi from the microcosms, the mite surface and the digestive tract were used to compare the feeding on dried-remoistened leaves, representing the initial stadium of decomposition, and partly decomposed litter. Additionally, food preference tests between sterilised litter and dried-remoistened leaves and exposition of litter and dried-remoistened leaves on soil surface were use d. Scheloribates laevigatus fed on the fungi growing on the dried and remoi stened grass leaves in the initial stadium of grass litter decomposition. T he crashed and partly destroyed fungal hyphae formed a food bolus in the me senteron. No leave pieces were observed in the food boli. The Scheloribates laevigatus individuals feeding on grass litter in a later decomposition st adium consumed plant debris, spores and fungal mycelium. Litter was less pr eferred by Scheloribates laevigatus than the dried-remoistened leaves in th e food preference tests. The Scheloribates laevigatus choice between the li tter and the dried-remoistened leaves was influenced by fungal communities. The sterilisation of leaves influenced the mite choice. The sterilised lea ves were not preferred in comparison to the non-sterilised ones in the pref erence tests. The exposition of leaves and litter on soil surface before th e experiment had no influence on the mite choice.