Biometria larval de duas Populaçoes de Simulium Oyapockense s.l. (Piptera: Simuliidae), provenientes de Paraíso (São Gabriel da Cachoeira, Am) e Cachoeira Bem-Querer (caracaraí, RR), Brasil

Abstract

The present study is based on the use of methodologies applied to the taxonomy of Simulium oyapockense Floch & Abonnenc, 1 946 (Di ptera: Simuliidae) , involved with transmission of human onchocerciasis in Brazilian Amazonial. S. oyapockense has been recognized as a complex composed of sibling species which differs in their biology, ecology and transmission potential. The larval instars were determined and a comparative diagnosis were carried out of two allopatric populations from the Cachoeira Bem-Querer, Rio Branco, in Caracaraí, Roraima State (0I055'N - 6I000'W), and Paraíso, Rio Negro, in São Gabriel da Cachoeira, Amazonas State (OOO1O'N - 67OOI'W). Paraíso is located about 200 km from San Carlos de Rio Negro (Venezuela), type locality of Simulium sanchezi Ramírez- Pérez, Yarzábal & Peterson, 1982, junior synonym of S. oyapockense, but this synonymy has been disputed. The immatures were collected in plant substrata, such as: leaves, twigs and in aquatic plants of the family Podostemaceae, available in each watercourse in the collected areas. A total of 800 larvae from each population were analyzed for determination of the larval instars. Using frequency histograms, the Crosby growth rule and Student-t Test six larval instars were determined for the population of the Cachoeira BeMuerer and seven instars for the population of the Paraíso, using measurements of the lateral size of the head and the cephalic apotome. For morphologic diagnosis of larvae, mature larvae were used and a comparative study was carried out of the larval cephalic structures of the two populations. The results suggests that the specimens collected in the different areas can be distinct species and provide new data to solution of problems related to the identity of the different species in the S. oyapockense s.1. complex.