Document Type : Research Article
Spiders are one of the most abundant invertebrates in terrestrial ecosystems that have a good potential to pest control in crops. Species richness and abundance of spiders and the effects of different agricultural practices on these predators were studied in winter wheat fields in Shirvan, Mashhad and Gonabad, cities in northeast of Iran. In each region, high and low input fields of winter wheat and a natural system were selected. Sampling was done by sweep net from the surface of plants in the fields and selected area of natural systems. Results showed that species richness of spiders was affected by climatic conditions. With increasing of mean annual precipitation and decreasing of mean annual temperature in studied regions, species richness of spiders increased. Spiders abundance was not affected by climatic conditions and in agricultural systems was higher than natural systems. Abundance of these animals was affected by management of agricultural systems, especially by conservation of trees around the fields. Although species richness of spiders was lower in dry region, but with proper management of agricultural systems, abundance of these animals and useful function of them will increase for pest control.