Spiders in Pecans in Central Texas

We studied the ground and canopy spiders in two pecan (Carya illinoinensis (Wangenh.) K. Koch) orchards located in central Texas, using pitfall traps and corrugated-cardboard-refuge traps in the canopies of trees. We identified 162 species, distributed in 26 families. The community of spiders in these two orchards represented ca. 15% of the species and ca. 50% of the families previously reported for Texas. The spider Camillina pulchra (Keyserling) was a new state record and was collected at both sites. In this study, 51 species were new records for Comanche County and 84 were new records for Robertson County. Spiders in this agroecosystem were abundant, and several species predominantly occurred either on the ground or in the canopy at both locations. We suggest that the consumptive presence of spiders in space and time indicates they constitute the principal natural enemies that contribute to maintaining endemic conditions (density levels < 0.1 of the carrying capacity for affected organisms) among arthropods in this, and perhaps other, terrestrial ecosystems throughout the year.