New records of the black fly fauna (Diptera: Simuliidae) in two rivers of the western Amazonia, Brazil

Novos registros da simuliofauna (Diptera: Simuliidae) em dois rios da Amazônia Ocidental, Brasil

SCIENTIFIC NOTE

New records of the black fly fauna (Diptera: Simuliidae) in two rivers of the western Amazonia, Brazil

Novos registros da simuliofauna (Diptera: Simuliidae) em dois rios da Amazônia Ocidental, Brasil

Érika S Nascimento; Verônica Marchon-Silva; Marilza Maia-Herzog

Lab. de Referência Nacional em Simulídeos, Oncocercose e Mansonelose, Instituto Oswaldo Cruz, Av. Brasil, 4365, Manguinhos, 21045-900 Rio de Janeiro, RJ

ABSTRACT

Our goal was to verify the presence and the composition of black floy species in the Antimari and Acre rivers, located in the end of Western Amazonia, where this entomological inquiry was accomplished. Along the Antimari and Acre rivers, 19 localities were studied and 133 larvae and 197 pupae were collected, totalizing 330 black floy immatures. The following species are recorded for the first time in this area: Simulium (Psaroniocompsa) amazonicum Goeldi, Simulium (Psaroniocompsa) oyapockense Floch & Abonnenc, Simulium (Psaroniocompsa) quadrifidum Lutz, Simulium (Psilopelmia) lutzianum Pinto, Simulium (Psilopelmia) perfloavum Roubaud and Simulium (Notolepria) exiguum Roubaud. Our data suggest that S. amazonicum, S. oyapockense and S. quadrifidum have a wide geographical distribution as well as population density.

Key words: Simulium, Acre, Amazonas, Antimari river, Acre river

RESUMO

O objetivo deste trabalho foi verificar a presença e composição de simulídeos nos rios Antimari e Acre, localizados no extremo oeste da Amazônia Ocidental. Foram levantados 19 pontos de coleta ao longo dos rios Antimari e Acre, onde foram coletadas 133 larvas e 197 pupas, totalizando 330 imaturos de simulídeos. As seguintes espécies foram encontradas pela primeira vez na região: Simulium (Psaroniocompsa) amazonicum Goeldi, Simulium (Psaroniocompsa) oyapockense Floch & Abonnenc, Simulium (Psaroniocompsa) quadrifidum Lutz, Simulium (Psilopelmia) lutzianum Pinto, Simulium (Psilopelmia) perfloavum Roubaud e Simulium (Notolepria) exiguum Roubaud. Os resultados sugerem que S. amazonicum, S. oyapockense e S. quadrifidum têm distribuição geográfica mais ampla e são mais frequentes nessa região.

Palavras-chave:Simulium, Acre, Amazonas, rio Antimari, rio Acre

The diversity of black floy species can be inflouenced by different environmental factors, as water flo ow, nutrient availability, the substratum readiness for fixation of immatures (Corkum & Currie 1987) and by anthropization. According to Moreira et al. (1994), the sources of pollution can also inflouence the species composition of lotic systems.

In the Brazilian Amazonia seven subgenera of Simulium are found: Simulium (Chirostilbia) Enderlein, represented by two groups of species; Simulium (Hemicnetha) Enderlein, with four groups of species; Simulium (Inaequalium) Coscarón and Wygodzinsky, represented by two groups of species; Simulium (Notolepria) Enderlin, with one group of species; Simulium (Psaroniocompsa) Enderlein, represented by six groups of species; Simulium (Psilopelmia) Enderlein, with five groups of species and Simulium (Trichodagmia) Enderlein, represented by one group of species (Adler & Crosskey 2008).

Despite the several taxonomic studies on the fauna from the rivers of the Brazilian Amazonia area, taxonomic and bionomics registrations for the family Simuliidae in Acre and Amazonas States are still scarce. Due to the importance of this family in the filarial transmission in Brazil and the lack of information on local species, studies have been addressing the black floy species distribution in the Antimari and Acre rivers, located in the Amazonia hydrographic basin, in the States of Acre and Amazonas.

The area selected for this study is located along the Antimari and Acre rivers, as well as in the tributary streams of these rivers, located in Acre and Amazonas States, in the Amazonia hydrographic basin (Fig 1).The Antimari river is a subsidiary of the Acre river and it reaches 66,168 hectares in the Center-East of the Acre State, in Bujari district. The Acre river is the main river of the drainage net of Rio Branco district and its drainage-basin area is of approximately 609.15 km² (ZEE-Acre 2000).

Black fly immatures sampling was conducted in July/2006 (dry season in the area) for a period of 15 days in natural substrate found at 19 selected point-nurseries in several courses of water, where temperature, water pH, geographical coordinates and altitude were recorded (Tables 1, 2).

The key of Adler & Crosskey (2008) was used for black fly species identifi cation.

From 133 larvae and 197 pupae collected, 39 adults emerged in 23 females and 16 males, totalizing 330 immatures identified as: Simulium (Psaroniocompsa) amazonicum Goeldi, Simulium (Psaroniocompsa) oyapockense Floch & Abonnenc, Simulium (Psaroniocompsa) quadrifidum Lutz, Simulium (Psilopelmia) lutzianum Pinto, Simulium (Psilopelmia) perfl avum Roubaud and Simulium (Notolepria) exiguum Roubaud (Tables 1, 2). According to our data, from the six species identified, S. amazonicum, S. oyapockense and S. quadrifidum were found to have a wider distribution and higher density, as they were collected in both rivers.

Simulium quadrifidum was collected in more than 50% of the samples, in the Antimari and Acre River, what corroborates Shelley et al (1997) report that this species is commonly found in the Brazilian Amazonia. Such species erroneously assumed epidemic importance when it was mistaken by Simulium amazonicum (Cerqueira & Nunes de Mello), which is the vector of the filaria Mansonella ozzardi. However, all these species can be successfully identified using adults reared from collected pharate pupae, and basing the identification on the pupae exuviae and the emerged adults (Shelley et al. 1982). Simulium amazonicum was also identified in Antimari and Acre rivers.

Simulium oyapockense, which is similar to Simulium roraimense Nunes de Melo and is anthropophilic, has been previously registered in Pará, Roraima, Rondônia, Amapá and Amazonas States (Shelley et al 1997). This species was collected in both rivers Antimari and Acre during this study. Simulium exiguum is also a vector and was registered only in the Acre river, Amazonas. In Brazil, this species is mainly zoophilic, but has been anthropophilic in Distrito Federal, Amazonas, Goiás, Mato Grosso, Roraima and São Paulo States (Shelley et al 1997).

Simulium lutzianum was only collected from the Auaris river in Brazil in one occasion and was found at Parima on the Venezuelan side of the onchocerciasis focus. It has a wide distribution outside the onchocerciasis focus (Shelley et al 1997). According to Adley & Crosskey (2008), this species was reported in Brazil in Goiás, Roraima, Paraná Santa Catarina and Rio Grande do Sul States. It was found in Antimari and Acre rivers, corroborating the reports of its occurrence in the Amazonian area.

Simulium perfloavum was found in Acre river, in three different collection sites, presenting zoophilic habit and wide distribution and was previously recorded in Amapá, Amazonas, Pará, Pernambuco, Rio Grande do Sul, Bahia, Goiás, Mato Grosso, São Paulo, Espírito Santo, Minas Gerais, Rio de Janeiro and Santa Catarina States (Crosskey & Howard 2004).

These new records of seven black floy species leads to the detection of a diversity of anthropophilic and zoophilic species in the Antimari and Acre rivers, as well as the presence of species vectors of mansonelliasis and onchocerciasis in endemic areas.

Acknowledgments

To the biologist João Torres for the aid in the collections and in whole field work. To Fundação de Tecnologia do Estado do Acre (FUNTAC) and to Departamento de Ações Básicas de Saúde, da Secretaria de Estado de Saúde do Acre (DABS/ SESACRE) for the support in the field collections. To Vice-Presidência de Pesquisa e Desenvolvimento Tecnológico do Instituto Oswaldo Cruz program to technologist - VPPDT, in agreement with Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro - FAPERJ, for financial support.

Received 11/IX/07. Accepted 15/VIII/08.

Edited by Neusa Hamada - INPA

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Publication Dates

• Publication in this collection
  25 May 2009
• Date of issue
  Apr 2009

History

• Accepted
  15 Aug 2008
• Received
  11 Sept 2007