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

Abstract

The panphytophagous oribatid mites Scheloribates laevigatus, Achipteria coleoptrata 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 assess the consumption and digestion of the offered diets. The mites consumed all the offered diets including fungi growing on litter. Marked differences 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 fungal and hyphal cell walls looked undamaged after the gut passage in all species. About the half of the algal cells were damaged mechanically and the contents of cells were digested. The fungi growing on litter were digested similarly. Litter was cut in small pieces by chelicerae, and no conclusions can be made about its utilisation. The results are discussed in view of the knowledge about the enzymatic equipment of the three oribatid species and recent feeding guilds.