Taxonomia de Odonata (Insecta), com ênfase na caracterização morfológica e biologia de larvas, na Amazônia Central, Brasil

Abstract

Odonata has a high diversity of species in tropical regions; however, major gaps in knowledge still exist in many biomes, including the Amazon rainforest. Most studies of Odonata in the Neotropics focus on adults. Thus, the taxonomy and biology of the immature forms are still little known: less than one-third of the species recorded from Brazil have their larvae described. The objective of this study was to increase knowledge of the taxonomy, distribution and biology of Odonata, with emphasis on larval stages in the Central Amazon. During the years 2008 and 2009 collections were made in approximate 150 well preserved streams to obtain adults and larvae in different localities and municipalities in the Amazonas State: Manacapuru, Manaus, Novo Airão, Presidente Figueiredo, Rio Preto da Eva, and the areas of environmental protection Reserva Florestal Ducke (Manaus), Reserva Biológica do Uatumã (Presidente Figueiredo) and Parque Estadual Serra do Aracá (Barcelos). The larvae were used for breeding under laboratory conditions. Identification of adults and associated larvae resulted in 175 species in 77 genera, 15 families already reported in Brazil, with 41 new records for the state of Amazonas, of which 22 were new for the country. Dimeragrion Calvert (Megapodagrionidae) is recorded for the first time in Brazil through the D. percubitale Calvert, collected in the region of the tepuis in Serra do Aracá (1115 m.a.s.l). Three new species are described, including a new genus (Coenagrionidae gen. nov. sp. nov.; Erythrodiplax sp. nov. and Gynacantha sp. nov.) from adults emerging under laboratory conditions. Thirteen last-instar larvae, hitherto unknown, are also described: Macrothemis rupicola Rácenis; Mecistogaster lucretia (Drury); Megapodagrion megalopus (Selys); Misagria divergens De Marmels; Mnesarete astrape De Marmels; Mnesarete cupraea (Selys); Orthemis attenuata (Erichson); Palaemnema brasiliensis Machado; Perilestes solutus Williamson and Williamson; Psaironeura tenuissima (Selys); Staurophlebia wayana Geijskes; Uracis siemensi Kirby and Zenithoptera lanei Santos. Keys are also provided for identification of families and genera of last-instar larvae known in the state of Amazonas and, when possible, for Brazil (except Libellulidae). Analysis of stomach contents of 992 larvae of Odonata, through dissecting the anterior intestine, collected from different substrates in streams located in the Reserva Ducke and Reserva Uatumã, showed that Chironomidae was the most abundant prey (38.4%) and was also the most frequent (41%), followed by Baetidae (13.6% and 17.8%), Leptophlebiidae (8.8% and 12%), Trichoptera (11.5% and 14.4%), Oligochaeta (5.2% and 6.7%), Simuliidae (4% and 4.7%) and Acarina (4.1% and 4.9%).