An account is given of the soil- and litter-dwelling microarthropods collected under three species of desert shrub in southern New Mexico. Particular attention is paid to the acarine component which represents 80% of the microarthropod fauna. Comparisons made with samples collected one hour after wetting show that only the Collembola respond rapidly to changes in the moisture content of the soil. The results of the study suggest that the depth and stability of the surface litter determine the degree to which microarthropod activity is affected by the application of water.