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Ichthyocladius is a genus of chironomid (Diptera, Insecta) whose immature forms live attached to the bodies of some species of freshwater fishes. Here we investigate the association between Ichthyocladius spp. and armored catfish in streams of the Guareí River basin, Paraná River system, Brazil. We provide the first record of I. lilianae associated with fish in the São Paulo State and the Paraná River basin. In addition, this is the first report of Ichthyocladius associated with the armored catfishes Hypostomus iheringii and H. tietensis. Lastly, we record two undescribed species of Chironomidae (i.e., Ichthyocladius sp. 1 and Ichthyocladius sp. 2) associated with fishes.

Epipelon can contribute to the maintenance of shallow lake oligotrophication. Herein, we simulated oligotrophication by diluting eutrophic water and evaluated epipelon biomass and structure and potential relationships with phytoplankton and zooplankton communities. Dilutions of 25-75% negatively impacted phytoplankton biomass and zooplankton diversity and increased Rotifera density. Additionally, the 25% dilution increased Copepoda density, but had no effect on Cladocera. On both experimental days, epipelon chlorophyll-a and algal density responded to oligotrophication, but the algal biomass response was less pronounced after 14 days. Ceratium furcoides was dominant in the phytoplankton, while diatom species were dominant in the epipelon. We observed that experimental oligotrophication can influence both the biomass and taxonomic structure of the algal and zooplankton communities. Overall, we concluded that experimental oligotrophication negatively impacted the phytoplankton biomass and favored the development of the phototrophic epipelon; however, a large reduction in eutrophication (>50%) is required for a significant algal response in the benthic environment of a shallow tropical reservoir., Competing Interests: Declaration of competing interest We declare no personal, academic, financial or institutional conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, the inverted trophic hypothesis was tested in the freshwater fish communities of a reservoir. The distribution of fish species in three freshwater habitats in the Jurumirim Reservoir, Brazil, was examined using both species richness and the relative proportions of different trophic groups. These groups were used as a proxy for functional structure in an attempt to test the ability of these measures to assess fish diversity. Assemblage structures were first described using non-metric multidimensional scaling (NMDS). The influence of environmental conditions for multiple fish assemblage response variables (richness, total abundance and abundance per trophic group) was tested using generalised linear mixed models (GLMM). The metric typically employed to describe diversity; that is, species richness, was not related to environmental conditions. However, absolute species abundance was relatively well explained with up to 54% of the variation in the observed data accounted for. Differences in the dominance of trophic groups were most apparent in response to the presence of introduced fish species: the iliophagous and piscivorous trophic groups were positively associated, while detritivores and herbivores were negatively associated, with the alien species. This suggests that monitoring functional diversity might be more valuable than species diversity for assessing effects of disturbances and managements policies on the fish community., (© 2019 The Fisheries Society of the British Isles.)

It is generally assumed that zooplankton can recolonize lakes that have been exposed to pesticides, via their dormant egg banks. Hitherto, few studies have evaluated the relative importance of dormant egg bank recruitment in the re-establishment of zooplankton communities in the presence of pesticide. This study investigated the effects of commercial products Bratt ® (a.i. 2,4-D), Roundup ® (a.i. glyphosate) and their mixture on the emergence (abundance and taxon richness) of dormant zooplankton egg banks from natural lake sediment. Sediment samples were collected from the surface sediment (<10 cm depth) in four lakes in Southeast São Paulo, Brazil. We performed a hatching experiment, in which natural lake sediments containing dormant eggs were exposed separately to Bratt ® (applied concentrations ranging from 0.30 to 20 mg L -1 ), Roundup ® (0.28-8.5 mg L -1 ), and combined mixtures of all concentrations, plus one control (non-exposure to formulated herbicides) for a period of 28 days. All tested concentrations of Bratt ® , Roundup ® and their mixture reduced the abundance and taxon richness of emerging zooplankton (except 2 mg L -1 of Bratt ® ). This effect was more pronounced in rotifers. In comparison, there were no negative effects on the emergence of microcrustaceans. These findings suggest that commercial products Bratt ® , Roundup ® and their mixture can suppress the emergence of rotifers, thereby influencing zooplankton recruitment potential in lakes impacted by the presence of these commercial herbicides. Our results stress the importance of the need for additional studies to assess the effects of pesticides on dormant egg banks., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Animals can be important in modulating ecosystem-level nutrient cycling, although their importance varies greatly among species and ecosystems. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater and marine animals of N and/or P excretion rates. These observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. This data set was used to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582)., (© 2017 by the Ecological Society of America.)