Trichoptera (insecta) em riachos do leste maranhense, Brasil

Abstract

Representatives of the order Trichoptera are considered environmental bioindicators because they are sensitive to changes in the environment related to some environmental and physicalchemical factors, in this sense, it is necessary to know the diversity of these representatives in aquatic environments. The present study aims to inventory the fauna of Trichoptera in the streams of the Eastern Maranhense, especially in the municipalities of Caxias and Codó. The collections were carried out in the streams: Baixa Grande II, Batatal, Buriti Corrente, Buriti Dantas, Cajazeiras and Sumidouro do Padre, in the substrates leaves, roots, trunks, macrophytes and submerged stones. In each stream, parameters were environmental and physical-chemical parameters. Trichoptera larvae were used for survey and breeding data in the laboratory. The streams dissipated average (22 cm). Average width (2.20 m), average speed (0.55 m / s), average flow (0.44 m³ / s), average temperature (26.74ºC), acidic water (4.22), electrical conductivity ( 60.55µS / cm), the average oxygen standards (12.73mg / l). 1,311 specimens of Trichoptera were collected, distributed in five families and eight genera, they are: Hydropsychidae: Leptonema, Smicridea, Macronema, Macrostemum; Philopotamidae: Chimarra; Leptoceridae: Nectopsyche; Helicopsychidae: Helicopsyche; Odontoceridae: Marília. The streams Baixa Grande II and Sumidouro do Padre secondary as greatest wealth of genera with six genera, followed by Buriti Corrente with five genera, Cajazeiras and Batatal with four genera, and Buriti Dantas with two genera. The substrate with the highest number of specimens was leaf (540 specimens), followed by stone (349 specimens), root (288 specimens), macrophytes (97 specimens) and trunk (37 specimens). The genera Smicridea and Chimarra were associated with leaf, Macrostemum with leaf and rais and Helicopsyche had association with stone. The streams Buriti Corrente and Baixa Grande II were similar, as well as Cajazeiras and Buiti Dantas. By breeding larvae in the laboratory, three adults of Trichoptera were chosen, which will be identified as the species level. The present work contributes to the knowledge of the order Trichoptera in the state of Maranhão and in the East of Maranhão, the results used in future studies of conservation and biomonitoring.