Irrigated rice fields form one of the most distributed agricultural landscapes on the world supplying food of billions of people. Surprisingly little is known on the structure of arthropod food webs in these systems and how they vary with management practices. Within the framework of the LEGATO project ("Land-use intensity and ecological engineering-assessment tools for risks and opportunities in irrigated rice based production systems") we plan to investigate the food web of tropical irrigated rice field production systems on the Philippines by studying the diversity and abundance of generalist predators (e.g. spiders) and their prey. I want to analyse the effects of different habitat types (irrigated rice paddies with poorly and highly structured surrounding landscapes) on generalist predators using suction sampling and sweep netting. Species will be identified and their abundance determined. Further, the trophic position of predator and prey species and the impact generalist predators may have on rice insect pests will be analysed using stable isotope technologies. Using stable isotope analysis basal carbon sources contributing to generalist predator nutrition will be analysed. In particular, I want to investigate the role of terrestrial vs. aquatic prey species to generalist predator nutrition. It is hypothesized that aquatic detritivores and herbivores contribute significantly to the functioning of ricefield food webs thereby affecting the role of generalist predators for controlling insect pest species of rice.