Influência de sistemas produtivos sobre a comunidade de predadores epígeos

Abstract

A new international guidance has been defined to the agricultural production, in order to use methods that are less harmful to the environment to promote the conservation and sustainable use of biodiversity. Thus, biological control of pests has been largely used. Among the natural enemies, predators are considered the first line of defense against phytophagous insects and studies indicate that the increase in abundance and effectiveness of natural enemies may be related to the heterogeneity and diversity of agroecosystems. Therefore, production systems can influence the occurrence of arthropod predators by the quality, quantity of supplied refuges and sources of available food. Thus, the aim of this study was to evaluate the influence of production systems in monoculture and integrated systems predatory epigeal arthropod community. The production systems evaluated in this study were: 1) crop monoculture of soybean in the summer and subsequent cultivation of maize intercropped with palisade grass; 2) forest monoculture of eucalyptus; 3) pasture monoculture of palisade grass and 4) Crop-Livestock-Forest Integration (CLFI). The experiment was designed for using a randomized blocks with four replications. To collect arthropod predators, five pitfall traps were installed in transect in the center of each replication. The traps remained in the field for about 24 hours and the frequency of collection was biweekly during the crop and monthly in the off season. A total of 27,675 arthropod predators were collected, divided into two classes: Insecta and Arachnida. Insecta represented by the orders Coleoptera, Dermaptera and Hymenoptera with seven families, 40 genera and 81 species. The other class was Arachnida, represented by the order Araneae with 10 families, 15 genera and 21 species. The findings in this study show that the assessed production systems, as well as the sampling periods during crops and off seasons influenced the community of predatory epigeal arthropods.. The results in this study show that Forest and Crop-Livestock-Forest Integration systems had great abundance for individuals in the family Formicidae, while Dermaptera, Coleoptera and Araneae were more abundant in crop and CLFI systems. The CLFI system proved to be the most favorable system for frequency and abundance of arthropod predators. It was found a significant reduction of predatory arthropod community in the off-season period, and the occurrence of predatory ants and spiders was registered in crop, CLFI and Forest monoculture systems during that period.