Feeding preferences and gut contents of three panphytophagous oribatid mites (Acari : Oribatida)

The panphytophagous oribatid mites Scheloribates laevigatus, Achipteria col eoptrata and Galumna elimata were reared under laboratory conditions on the green bark alga Desmococcus vulgaris (syn. Protococcus viridis), grass and herb litter (Holcus lanatus, Hypericum maculatum and Acetosella vulgaris) including fungi growing on the litter, and filter paper. Food preferences, defaecation, gut contents and types of food boli were studied in order to a ssess the consumption and digestion of the offered diets. The mites consume d all the offered diets including fungi growing on litter. Marked differenc es in food preference between the alga and litter and no marked differences among mite species were observed. No visible differences in the degree of digestion of the three offered diets among the species were found. The fung al and hyphal cell walls looked undamaged after the gut passage in all spec ies. About the half of the algal cells were damaged mechanically and the co ntents of cells were digested. The fungi growing on litter were digested si milarly. Litter was cut in small pieces by chelicerae, and no conclusions c an be made about its utilisation. The results are discussed in view of the knowledge about the enzymatic equipment of the three oribatid species and r ecent feeding guilds. (C) 2001 Editions scientifiques et medicales Elsevier SAS.