Estimation of dry mass of caddisflies Phylloicus elektoros (Trichoptera: Calamoceratidae) in a Central Amazon stream

Abstract

ABSTRACT. Aquatic invertebrate biomass estimations are often important in ecological and biological studies. Biomass may be determined by regression models between body and case dimensions and dry mass. Using linear, exponential and power regressions we analyzed the relationship between body and case dimensions and the biomass of Phylloicus elektoros Prather, 2003. Furthermore, we used cross-validation to evaluate the predictions of our models and of the models developed for Phylloicus sp. from southeastern Brazil. We measured four body dimensions (head capsule width, interocular distance, body and pronotum length) of 152 larvae and two case dimensions (width and length) of 45 cases. Case width provided better fit with biomass than case length in all model classes. Body length provided the best biomass prediction. Biomass predictions using models proposed in the literature were 75% lower than the observed values. The power model provided the best fit between body and case dimensions with biomass. However, exponential models also provided good biomass estimates. We observed a close fit between body and case dimensions and biomass, but the predictive power of the models was low (~40%). The predictive power of models proposed in the literature was much worse than those built from local data and thus we do not recommend their use to predict the biomass of organisms from different regions.

Effects of increasing temperature and, CO2 on quality of litter, shredders, and microorganisms in Amazonian aquatic systems

“…We incubated leaves in the stream to allow natural conditioning before the leaves were broken down by shredders and microorganisms. The stream has dense riparian forest, acidic water (pH = 4.6 ± 0.1), high dissolved oxygen concentration (6.6 ± 0.1 mg l -1 ), low electrical conductivity (10.7 ± 0.4 αS cm -1 ) and mean temperature of 24.5 ± 0.5°C [ 29 ]. The leaves were then cut into discs (14 mm in diameter), avoiding the midrib.…”

“…elektoros larvae. This species is an important shredder in Amazon streams [ 29 ]. The larvae are usually abundant in pool mesohabitats [ 30 ], favoring their use in laboratory experiments.…”

“…Ecological aspects of shredder invertebrates in tropical ecosystems have been tested in experimental studies, mainly using Phylloicus caddisflies (e.g., [ 25 , 28 – 29 ]). This genus is present in South and Central American countries [ 30 ].…”

Catalog of the Neotropical Trichoptera (Caddisflies)

“… Moretti et al (2009) showed that Phylloicus selected leaves for case-building that were chemically protected againt microbial degradation and consumption by other shredders, but this was dependant on leaf abundance. As a typical and important leaf shredder in Neotropical aquatic ecosystems, Phylloicus has been been the subject of many different kinds of biological and ecological studies, perhaps the most of any caddisfly in the region (e.g., Rincón and Martínez 2006 , Wantzen and Wagner 2006 , Becker et al 2009 , Encalada et al 2010 , Landeiro et al 2010 , Navarro et al 2013 , Vidovix et al 2013 , Guzmán-Soto and Tamarís-Turizo 2014 , Martins et al 2014 , Rezende et al 2015 ).…”

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

“…Phylloicus' larvae are commonly found on submerged leaf litter (Prather, 2003). It is the most abundant shredder taxon in Cerrado (Rezende et al, 2014(Rezende et al, , 2015 and Amazonian headwater streams (Martins, Melo, Gonçalves, & Hamada, 2014;Martins et al, 2015). Phylloicus is a typical shredder and uses leaf litter deposited in pool areas on streams bed to obtain their food and material to case construction (Wantzen & Wagner, 2006).…”