SOIL MITES IN DETRITAL FOOD WEBS OF CONVENTIONAL AND NO-TILLAGE AGROECOSYSTEMS

Field and laboratory studies were initiated in June, 1987 to investigate the feeding habits and temporal dynamics of litter mites from conventional and no-tillage agroecosystems. Experimental manipulations of saprophytic fungi with the fungicide Captan in the field were used to investigate the interactions and coupling of mites and fungi in detritus food webs of these systems. Applications of a functional trophic classification, based on laboratory feeding trials, indicated the dominance of fungivory in litter from both agroecosystems as compared to the traditional suborder classification. Predatory mites made up a considerably larger proportion of the total mite communities on buried litter than surface litter from both tillages. Captan strongly reduced fungal hyphal densities on surface and buried litter from both tillage treatments over the study period. The dominant fungivore mite families (Oribatulidae, Oppiidae, Haplozetidae and Tarsonemidae) were also reduced in Captan treated litterbags as compared to controls, suggesting tight coupling between fungi and fungivore mites in these agorecosystems.