Aquatic Insect Herbivore Functional Community Traits Respond to a Different Niche Between a Riparian and Sugar Cane Leaf Litter Processing.

Abstract

The niche of aquatic insect herbivores can be determined by the resource quality of leaf litter species. We compared the niche functional trait of aquatic insect herbivores between Magnolia ovata (riparian tree) and Saccharum officinarum (sugar cane) leaf litter processing. We hypothesized M. ovata and sugar cane leaf litter species would influence different functional traits niche of aquatic insect herbivores due to different quality resource leaves. We performed colonization experiments using dry leaves in five streams during 30-34 days. We utilized five replicates per leaf litter (n = 25) containing 12 g of dry leaves. We compared the niche specialization of herbivore functional traits using the Community Weight Mean (CWM) index and throughout herbivore abundance and the similarity composition of taxa. Additionally, we analysed the influence of organic matter in the CMW index of herbivore functional trait niche. We observed a higher abundance of shredders than scrapers in both leaf litter species. The M. ovata leaf litter selected a more specialized niche of respiration trait composed mainly chironomid shredder larvae, with the osmotic mechanism. The community structure differs weakly with a stronger and positive relationship between organic matter and respiration CWM index in riparian than sugar cane leaf litter. Concerning different composition communities between leaf plants, we consider that aquatic insect herbivore demonstrates a preference to leaf litter species with a specific resource. Additionally, most taxa adapt their feeding habit dependent on the availability of resource food.