Leaf litter quality drives the feeding by invertebrate shredders in tropical streams

Abstract

Amazon and Cerrado‐forested streams show natural fluctuations in leaf litter quantity along the time and space, suggesting a change on litter quality input. These natural fluctuations of leaf litter have repercussion on the organic matter cycling and consequently effects on leaf decomposition in forested streams. The effects of the quantity of leaf litter with contrasting traits on consumption by larvae of shredder insects from biomes with different organic matter dynamics have still been an understudied question. The Trichoptera Phylloicus spp. is a typical shredder in tropical headwater streams and keep an important role in leaf litter decomposition. Here, we assessed the consumption by shredder Phylloicus spp., from Amazonia and Cerrado biomes, on higher (Maprounea guianensis) and lower quality leaves (Inga laurina) in different proportions and quantities. Experiments were performed concomitantly in microcosms approaches, simulating Cerrado and Amazonian streams. Higher leaf consumption occurred in Cerrado microcosms. Litter quantity influenced negatively leaf consumption by shredders in Cerrado, in opposition to Amazonia, where consumption was not affected by leaf quantity. In both sites, we observed higher consumption by shredders in treatment with only M. guianensis and no difference between other treatments with mixture of leaves. In treatment with litter of I. laurina, we noted the use of substrate for case building (due to the higher leaf toughness), affecting the fragmentation process. Therefore, our results indicate that leaf litter quality drives the preference of consumption by Phylloicus larvae in Cerrado and Amazonia streams.

Do methodological differences in experiments with stream shredders imply variability in outputs? A microcosm approach

“…To carry out the experiments, shredders were collected in the Barro Branco stream, located in the Ducke Forest Reserve (02° 55' and 03° 01'S, 59° 53' and 59° 59'W), in the municipality of Manaus (Amazonas, Brazil). This stream has a closed canopy, acidic water (pH = 4.6 ± 0.1), dissolved oxygen of 6.6 ± 0.1 mg/L, and mean temperature of 24.5 ± 0.5°C (Martins et al 2020). We manually collected larvae of Phylloicus elektoros Prather, 2003 and Triplectides egleri Sattler, 1963 pool areas with litter accumulation.…”

“…Future studies should consider the feasibility of assessing the consumption of Phylloicus and Triplectides species sampled in the same biome or region to broaden the general understanding of these shredders for Neotropical stream ecosystems, given that studies often compare only one congener in different biomes (e.g., Phylloicus sp. ; Sena et al 2020;Rezende et al 2021;Ferreira et al 2023). In addition, in the experiments that use Phylloicus as a model organism and that evaluate foliar consumption, attention should be paid to the possible consumption of the cases themselves, as well as the use of discs to expand the cases, to avoid underestimating or overestimating the consumption.…”

“…Such experiments can be particularly useful in evaluating the roles of speci c organisms or groups of organisms (Goodman et al 2016; Cooke et al 2017). For example, shredder invertebrates are frequently used in laboratory and eld studies due to their critical role in organic matter processing in forested streams (Boyero et al 2007; Graça and Cressa 2010; Martins et al 2017aMartins et al , 2020. In these ecosystems, leaf detritus is the main basis of the food web because the shading of the riparian vegetation leads to reduced autochthonous primary production (Wallace et al 1997 In neotropical regions, speci cally Amazon streams, the main shredders are caddis ies belonging to the genera Phylloicus (Calamoceratidae) and Triplectides (Leptoceridae; Landeiro et al 2008Landeiro et al , 2010.…”

Aquatic macro invertebrate contribution in leaf litter breakdown in tropical mining area streams (Cte dIvoire, West Africa)

“…Among the macro-invertebrates, macro-invertebrate shredders are selective organisms which play important role in breakdown fluxes of leaf litters (Sena et al, 2020). Under natural conditions, streams litter is made up of leaves of various plant species.…”

Immature life cycle of laboratory-reared Phylloicus elektoros and Phylloicus amazonas (Trichoptera: Calamoceratidae) from a central Amazonian stream

“…Phylloicus Müller, 1880 (Trichoptera: Calamoceratidae) species are fundamental shredders in low-order Neotropical streams (Martins et al 2015;Souza-Holanda et al 2020). Due to their importance in the decomposition of organic matter in aquatic environments, Phylloicus larvae have been used in several laboratory experiments (e.g., Martins et al 2017a,b;Martins et al 2020;Rezende et al 2020;Sena et al 2020).…”