Campsurus truncatus Ulmer, 1920 (Polymitarcyidae): an Ephemeroptera in eutrophic waters

Mônica Luisa Kuhlmann,Hélio Rubens Victorino Imbimbo,Helena Mitiko Watanabe

doi:10.1590/s2179-975x10019

Mônica Luisa Kuhlmann, Hélio Rubens Victorino Imbimbo + Show 1 more

Open Access

https://doi.org/10.1590/s2179-975x10019

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Abstract

Abstract: Aim The order Ephemeroptera, together with Trichoptera and Plecoptera, has been considered as sensitive in environmental quality assessment. However, the species Campsurus truncatus Ulmer 1920 (Polymitarcyidae) has been sampled in anthropically altered sites. In this paper, data on the occurrence of that species in the water quality monitoring network of the Environmental Agency of São Paulo State (CETESB) were gathered to review its position in the environmental gradient and in the quality assessment of rivers and reservoirs. Methods For this, a compilation of the occurrences and densities of Campsurus obtained in rivers and reservoirs of São Paulo state between 2001 and 2018, with grab samplers, was carried. Environmental factors, the Trophic State Index (TSI) and the Benthic Community Index (BCI) were related to the species densities to define its environmental requirements. Results The sublittoral zone of reservoirs was the most common habitat to C. truncatus, occurring more frequently at mesotrophic sites with fair ecological quality. Higher mean densities were recorded at eutrophic sites with good ecological quality conditions. The statistical analysis did not show linear correlation between C. truncatus densities and any of the analyzed environmental variable such as grain size, organic matter content, DO and light penetration, although there was a tendency for higher species densities occur in muddy, dark sediments and with intermediate levels of organic matter. As described in literature the presence of aquatic plants can actually benefit that population once the highest densities were observed in sites with many macrophytes, as Salto Grande reservoir, but it may be confusing the relationship between population density and environmental factors. Conclusions The high occurrence and densities of C. truncatus obtained in eutrophic environments suggest that the species should not be considered as a sensitive taxon in qualitative indexes, such as the BCI for rivers and the sublittoral region of reservoirs. Moreover, its exclusion from the richness of sensitive groups had low impact on the diagnoses already performed at the CETESB monitoring network.

Highlights

The Polymitarcyidae family of aquatic insects of the Ephemeroptera order is widespread, occurring at Holartic, Ethiopian-Oriental and Neotropical regions (Domínguez et al, 2006)
The high occurrence and densities of C. truncatus obtained in eutrophic environments suggest that the species should not be considered as a sensitive taxon in qualitative indexes, such as the Benthic Community Index (BCI) for rivers and the sublittoral region of reservoirs
Campsurus truncatus Ulmer 1920 occurs in Brazil, Bolivia, Colombia and Peru (Molineri et al, 2015)

Summary

Introduction

The Polymitarcyidae family of aquatic insects of the Ephemeroptera order is widespread, occurring at Holartic, Ethiopian-Oriental and Neotropical regions (Domínguez et al, 2006). Campsurus is the genus with the highest number of species, 28 (Molineri et al, 2015). Their nymphs burrow U-shapped tunnels in bottom sediments of lentic habitats (Domínguez et al, 2006). Campsurus truncatus Ulmer 1920 occurs in Brazil, Bolivia, Colombia and Peru (Molineri et al, 2015). At Águas Claras reservoir (State of MG/Brazil), specimens of C. truncatus reached 2.4 cm in length and its population, with high secundary production (3.2 g.m-2.year-1), was classified as multivoltine, with the aquatic phase lasting between 16 and 24 weeks (Lima & Pamplin, 2017). The potential high secondary production of the species is an important issue for the energy flow and nutrient cycling for the aquatic system, as they are preferential food item for some fish species (Meschiatti, 1995). It has been reported that populations of the genus play a significant role in the sediment bioturbation (Leal et al, 2003; Figueiredo-Barros et al, 2007), with potential to alter the carbon cycle (Leal et al., 2007) that, in impacted environments, can lead to the resuspension of contaminants and nutrients accumulated in the sediments to the water column

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