EFFECTS OF DIFLUBENZURON ON THE LITTER SPIDER AND ORTHOPTEROID COMMUNITY IN A CENTRAL APPALACHIAN FOREST INFESTED WITH GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE)

We searched for effects of diflubenzuron treatment on numbers and dive rsity of two groups of litter arthropods-spiders (Araneae) and orthopt eroid insects (Orthoptera and Dictyoptera)-in a West Virginia hardwood forest infested with gypsy moth. We established sampling stations con sisting of pitfall traps in treated and untreated plots (four each) an d sampled for up to 75 d following spray. Variability in dependent var iables (habitat differences) was reduced by performing principal compo nents analysis on habitat variables and by introducing the principal c omponents into the treatment effect models as covariates. A treatment effect was apparent from 21 to 42 d after spray in both spider and ort hopteroid insect abundance, although the effect was significant on onl y two sample dates for orthopteroid insects. There was no treatment ef fect on species diversity for these two groups.