Trophic resources use pathways between two coexisting freshwater shrimp (Palaemon argentinus and Macrobrachium borellii)

Abstract

Context. A better understanding of the use of different trophic pathways as a mechanism for adjusting interactions between coexisting omnivorous decapod species may help define the extent of their influence on energy flows in freshwater ecosystems. Aim. Analyze the patterns of use of the benthic and littoral pathways by M. borellii and P. argentinus during a hydrological cycle in lakes of the middle Paraná River. Methods. The study was conducted during one high water period (HW) and one low water (LW) period in three lakes permanently connected to the middle Paraná River. We calculate the relative contributions of potential basal resources (benthic and littoral) to each species for each lake and hydrological period using mixing models. Key results. It was observed that M. borellii feds more in the littoral pathway and P. argentinus in the benthic pathway, especially in low water where we observe that the partitioning of resources is more pronounced. Implications. This may have important consequences in the aquatic trophic webs in which these organisms participate, since when segregating the use of resources, they intervene in different energetic pathways.