Interactions between Invertebrates and Microfungi in Freshwater Ecosystems

Abstract

The importance of detritus metabolism in aquatic ecosystems has been stressed by various authors since at least the 1930s. There is evidence now that detritivorous species feed on the microfungi attached to the leaf detritus rather than the detritus itself and that these are a high quality food. Moreover, the numerous species of microfungi colonizing leaf detritus are important in making it a heterogeneous food resource for coexisting detritivores. The fungi present on leaf detritus in low abundance constitutes many different niche refuges shared among coexisting animal species. On the other hand, the abundance of fungi can be affected by foraging strategy of animals. Trophic niche plasticity of each animal population mediates the resource partitioning in detritus systems. The population niche width depends on the genotype arrangement of generalists and specialists. This arrangement seems established by predation pressure as well as competition. Thus, abundance of microfungi, niche width of detritivores and species packing in freshwater detritus communities are interdepedent aspects of a complex ecological system.