SPIDERS OF AN OLD FIELD HABITAT IN THE DELTA OF MISSISSIPPI

Over a 14-month period, 2785 spiders of 70 species were collected by 1 14 pitfall trap samples and 68 sweepnet samples in a 2.5 ha abandoned horse pasture adjacent to a cotton field in Washington County, Mississ ippi. Mean numbers of spiders per sample were approximately equal by p itfall (xBAR = 15) and sweepnet (xBAR = 16) methods. Individuals of th e Lycosidae (42.6%), Thomisidae (16.2%), and Salticidae (14.4%) compri sed almost three-fourths of all spiders collected. Individuals of 13 o ther families were also collected. Web-spinners comprised 21.4% of the species (n = 15) and 13.9% of the individuals (n = 386), whereas wand erers comprised 78.6% of the species (n = 55) and 86.1% of the individ uals (n = 2399). Eighteen species occurred only in the sweepnet (folia ge) samples, 31 species only in the pitfall (ground) samples, and 21 s pecies occurred in both sampled strata. Foliage spiders (mostly immatu res) reached peak population levels in June and July and again in Octo ber and November. Very low densities occurred in August and September, with intermediate levels throughout the winter and spring leading to peak adult densities in April. Ground spiders reached peak population levels in March (mostly adults) and July (mostly immatures). A compari son of the composition and structure of this spider community with oth er old field sites and other potentially adjacent crop and non-crop ha bitats suggests considerable similarity. A possible role for spiders i n cotton pest management is considered.