RESUMO
Arachnofauna (Araneae: Araneae) in transgenic and conventional cotton crops (Gossypiumhirsutum) in the North of Santa Fe, Argentina. Spiders have considerable potential importance for their role as predators to some pests in agricultural systems. The composition of spiders in transgenic and conventional cotton at the Research Station of INTA Reconquista (Santa Fe) was studied during the 2005-2006 season. The experiment was a complete randomized block design with three replications and three treatments: transgenic Bt cotton (ALBt), conventional cotton without chemical control (ALCSC), and conventional cotton with chemical control (ALCCC). Weekly, spiders were collected using nets, vertical cloth and pitfall-traps. A total of 1 255 specimens (16 families, and 32 species) were collected. Seven families were found in all the treatments, mainly Thomisidae (n=1 051, 84.04%) and Araneidae (n=83, 6.64%). The Hunting spiders guild ambushers (n=1 053, 83.91%), “Orb weavers” (n=85, 6.77%) and “Stalkers” (n=53, 4.22%) were more abundant. There were no significant differences in the indexes diversity between treatments. Spiders were presented during the whole crop season, with peaks about flowering and boll maturity, with the highest abundance in ALBt. This work is part of the first set of data registered in Argentina about spider’s community in cotton crops. Rev. Biol. Trop. 60 (2): 611-623. Epub 2012 June 01.
Las arañas tienen un valor potencial considerable por su rol depredador de insectos, estas son plagas de la agricultura. Durante la campaña agrícola 2005/06, en INTA Reconquista, Santa Fe (Argentina) se estudio la composición de arañas presentes en cultivos de algodón transgénico y convencional, mediante un diseño experimental de bloques completos al azar, con tres repeticiones y tres tratamientos: algodón transgénico Bt (ALBt), algodón convencional sin control químico (ALCSC) y con control químico (ALCCC). Semanalmente, se capturaron arañas, con una red entomológica de arrastre, paño vertical de 1m y trampas de caída. Asimismo se recolectaron 1 255 ejemplares (16 familias y 32 especies). Siete familias se presentaron en los tres tratamientos, donde predomino Thomisidae (n=1 051, 84.04%) y Araneidae (n=83, 6.64%). El gremio cazadoras por emboscada (n=1 053, 83.91%), “Tejedoras de telas orbiculares” (n=85, 6.77%) y “Cazadoras al acecho” (n=53, 4.22%) fueron las más abundantes. No hubo diferencias significativas en los índices de diversidad entre tratamientos. Las arañas se presentaron durante todo el ciclo del cultivo, con picos en las semanas de floración y madurez de las capsulas, además la mayor abundancia la encontramos en el ALBt. Este trabajo constituye el primer registro sobre la comunidad de arañas en cultivos de algodón para Argentina.