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 diversity of two groups of litter arthropods-spiders (Araneae) and orthopteroid insects (Orthoptera and Dictyoptera)-in a West Virginia hardwood forest infested with gypsy moth. We established sampling stations consisting of pitfall traps in treated and untreated plots (four each) and sampled for up to 75 d following spray. Variability in dependent variables (habitat differences) was reduced by performing principal components analysis on habitat variables and by introducing the principal components into the treatment effect models as covariates. A treatment effect was apparent from 21 to 42 d after spray in both spider and orthopteroid insect abundance, although the effect was significant on only two sample dates for orthopteroid insects. There was no treatment effect on species diversity for these two groups.