Spiders (Arachnida, Araneae) associated to agroecosystems in the Elqui Valley (Coquimbo Region, Chile)

The taxonomic composition of spiders associated with both cultivated areas and dry uncultivated sectors in the Elqui River Valley (Coquimbo Region, Chile) were examined by surveys within an altitudinal transect. A total of 230 specimens were captured. Taxonomically, 19 families and 29 species were obtained. Species richness was higher in the dry uncultivated sectors (23 species) than in the cultivated sites (18 species). Eight families were common to both situations; these were Anyphaenidae (1.3% of total capture), Araneidae (5.6%), Gnaphosidae (8.6%), Lycosidae (3.0%), Sicariidae (32.2%), Theridiidae (15.7%), Titanoecidae (3.5%) and Zodariidae (6.5%). The more abundant species in the semiarid area were Sicarius sp. (Sicariidae) (17,6% of total capture in the area), Steatoda porteri (Theridiidae) (9.5%) and Cybaeodamus lycosoides (Zodariidae) (9.5%). In the cultivated areas, in turn, the numerically dominant species were Loxosceles laeta (Sicariidae) (42.7%), Steatoda grossa (Theridiidae) (8.5%) and Goeldia patellaris (Titanoecidae) (8.5%). This paper is the first approach to the study of spider assemblages found in the semi-arid watersheds of Chile and sets the taxonomic bases for examining the role played by these organisms in integrated pest management or biological control.