The family Amplullaridae belongs to this class Gastropoda and is made up of freshwater organisms with a wide geographical distribution in tropical regions. Oligochaeta worms can be found in association with snails of this family, inhabiting the umbilicus of their shells. Due to the lack of information on the ecology of these worms, this work focused on investigating which kind of Oligochaeta species associate with the mollusk Pomacea bridgesii (Reeve, 1856). Samples were collected during winter and spring 2003 and summer 2004. From a total of 209 snails collected, the presence of Oligochaeta worms was observed in only 58 of them (27.75%). In these infected snails, 89 Oligochaeta worms were found, all belonging to the family Naididae. The species Haemonais waldvogeli Bretscher, 1900, Dero (Dero) nivea Aiyer, 1929 and Dero (Dero) sawayai Marcus, 1943 were the most abundant (43.68%, 12.32% and 10.08%, respectively). Haemonais waldvogeli was found in all of the seasons studied, what demonstrates its affinity for this kind of substrate. The results indicate that several Naididae species find in the umbilicus of these snails's shells (which contains fine detritus) a favorable habitat for establishing themselves.

No abstract

Mosses and liverworts can be colonized by various invertebrates, including fresh water oligochaete worms. However, little information is available on the habits and habitats of this oligochaetes in Brazil. Therefore, the present study was undertaken to examine the occurrence of naidids in mosses, as well as to broaden the knowledge about the habitats of these oligochaetes. Sampling of bryophytes adhered to rock substrates in the rapids of the Jacaré Pepira River (municipality of Brotas, São Paulo, Brazil) and to a vertical rock wall of a waterfall near the river revealed 191 Naididae individuals of the species Naiscommunis Piguet, 1906, Pristinellajenkinae (Stephenson, 1931) and Pristinellamenoni (Aiyer, 1929). We believe this to be the first record of naidids associated with mosses in Brazil.

Os inventários de espécies fornecem amplo conhecimento sobre a distribuição, ecologia e riqueza dos táxons tornando-o uma ferramenta importante para programas de conservação de biodiversidade e gestão dos ecossistemas. Os organismos inventariados neste estudo são pertencentes à classe Oligochaeta, um importante táxon da fauna aquática continental e um dos grupos mais importantes na ciclagem de matéria orgânica nos ecossistemas de água doce. Dessa forma, este estudo tem como objetivo realizar o levantamento das espécies de Oligochaeta em três córregos urbanos (Córrego Himalaia, Ribeirão da Bocaina e Córrego Bocaina) do município de Bocaina, localizado na região central do estado de São Paulo. Para isso, as amostras de sedimento foram coletadas em sete pontos com o auxílio de uma rede (malha 0,25 mm) pelo método de varredura. O material coletado foi triado para obtenção dos organismos, fixado com formalina 10% e identificado até nível de espécie. Foram registrados 20 táxons de um total de 1395 organismos, distribuídos em 10 gêneros (Allonais, Aulophorus, Bothrioneurum, Brinkhurstia, Dero, Limnodrilus, Nais, Opistocysta, Pristina e Slavina) e 4 famílias: Família Naididae Opistocystidae, Alluroididae e Enchytraeidae. Assim, o presente inventário obteve uma riqueza de 20 táxons, representando aproximadamente 23% das 86 espécies registradas em ecossistemas aquáticos brasileiros. Por fim, muitos estudos ainda precisam ser realizados para fornecer dados mais completos sobre a distribuição e ecologia desse táxon, para enfatizar sua importância como bioindicadores de qualidade da água e para manutenção do equilíbrio ecológico em ambientes aquáticos.

In Brazil, innumerable regions of native landcover have been removed and replaced by agricultural cultivation, especially of sugarcane. In this culture, the application of fertilizers containing metals has caused impacts on the water resources causing contamination of stream sediments and occasioning bioaccumulation of metals in aquatic invertebrates. In the year of 2006, an environmental diagnosis of metals in sediments of streams located near sugarcane cultivation areas and in streams located in preserved areas, was published. That study pointed to high concentrations of metals in stream sediments in agricultural areas. These streams have been monitored over the last 10 years conducting analyses of metals and monitoring possible changes in land use. In the present paper, a historical comparison of metals contamination in the sediments of the same streams is conducted, aiming to present a status of 10 years later, analyzing 5 metals (Zn, Cd, Mn, Cr and Fe) found in the sediments of 8 streams, five located in areas of sugarcane cultivation and three located in preserved areas. This study also shows that there is higher concentration of metals in the sediments of streams near sugarcane cultivation than in preserved areas. The temporal historical evaluation showed high concentrations of Cd in 2016 when compared to the year 2006 for streams near sugarcane cultivation.

No abstract

Oligochaeta are suitable for assessing the effects of contaminants on the environment, but in Brazil, few studies have been developed for the use of native species in toxicity bioassays. Given the increasing interest in this research area by the environmental agencies for the usage of species of aquatic Oligochaeta in ecotoxicological studies, in addition to the need for greater biological knowledge of native species, the present work aimed to establish a protocol to be used in ecotoxicological bioassays using the native species Allonais inaequalis. The Naididae A. inaequalis (Stephenson, 1911) was first described as Nais pectinata var. inaequalis Stephenson, 1911. The distribution of this species has been mentioned for several environments in Brazil. This paper presents results from tests on the sensitivity of the species to KCl (LC 50) and to zinc chloride (LC 50), the general characteristics of the species and laboratory breeding methods. Laboratory rearing, the collection and identification of the organism are easy when compared to other organisms such as Chironomus xanthus, a species commonly used in toxicity bioassays. It is expected that this work will assist in the use of A. inaequalis species for routine water monitoring protocols for tropical environments.

In the agricultural cultivation, the Pyrimethanil (4,6-dimethyl-N-phenyl-2-pyrimidinamine) fungicide is one of the most widely used compound in monocultures and has been detected in aquatic ecosystems. These genotoxic products increase the frequency of lesions in the DNA molecule, thereby increasing the risk of replication and transcription of altered DNA sequences. This study aimed to assess the loss of genetic diversity of Chironomus sancticaroli, a Brazilian native insect species, exposed to Pyrimethanil fungicide, using RAPD-PCR (random amplified polymorphic DNA) technique. The results showed that there was significant loss in the genetic diversity in the organisms exposed to high Pyrimethanil concentrations when compared with control site. Our findings reveal that RAPD-PCR is an effective method to access genetic loss derived to fungicide use and that the agriculture application may lead to a decrease in aquatic biota genetic diversity. This finding has important implications for conservation strategies and ecological management environments.