In most of the hot desert areas of North America, fluff grass, Erioneuron pulchellum is the most common perennial grass in desert shrub habitats. E. pulchellum is heavily utilized by subterranean termites (Whitford et al., 1982). As part of a study to examine faunal effects on the decomposition of E. pulchellum litter (Silva et al., 1985), we studied the sequence of microarthropod colonization and seasonality of microarthropod populations in E. pulchellum litter. These data provide a useful comparison with data on shrub litter microarthropod fauna and allow an assessment of effects of subterranean termite activity on that fauna. Experimental studies by Steinberger et al. (1984) demonstrated that the population densities of microarthropods vary as a function of the quantity of litter. Whitford et al. (1982), Silva et al.(1985) and Whitford et al.(1988) showed that in the Chihuahuan Desert, subterranean termites remove at least 50% of the annual above ground dry matter production. Based on these observations we hypothesized that termites could substantially reduce suitable habitat for microarthropods hence competitively reduce population sizes of microarthropods. Here we report the results of studies designed to test these hypotheses.