Influence of Trichodactylus fluviatilis on Leaf Breakdown inStreams: Understanding the Role of Freshwater Crabs in Detritus-based FoodWebs

摘要

Freshwater crabs can affect leaf breakdown by consuming leaves orinvertebrate shredders. The aims of this study were to analyze the gut content of and evaluate the influence of thismacroconsumer on leaf breakdown. For this, we (i) performed gut analyses of 55 individualsof and (ii) determined leaf decay rates and FPOMproduction in laboratory trials containing crabs and the caddisfly shredder sp., alone and together, and leaves differing in quality.We hypothesized that feeds both on leaves and sp. and, consequently, leaf decay rates would be lowerwhen these organisms were together. The main food categories in guts were algae and FPOM, while CPOM and animal tissue were rare. Leaf decayrates and FPOM production did not differ across shredder treatments or leaf species.However, the survival of sp. was higher when alone. Theresults support the potential for participation of in leafbreakdown and demonstrated that, in spite of the high abundances of algae and FPOM in thegut content, adults of this species have the potential to feed both on leaf litter andlarvae of sp. However, the hypothesis of this study was onlypartially corroborated because decay rates did not change across treatments.