Spatial and temporal distribution of blackflies (Diptera: Simuliidae) in the Itatiaia National Park, Brazil

The distribution of the blackfly larval taxocenoses of different altitudes in the Itatiaia National Park (located in the southeast of Rio de Janeiro state, Brazil 44°34' - 44°42' W , 22°16' - 22°28' S) was investigated on four campaigns, one in each season of 2003. On each campaign 60 samples were collected, using 30 x 30 cm wooden quadrats, distributed at four sites: Taquaral, Véu da Noiva, Três Picos and Brejo da Lapa. The winter and spring campaigns included two additional sampling sites: Alsene and Agulhas Negras. A total of 3578 larvae and 292 pupae were sampled, representative of six species: Simulium clavibranchium Lutz, S. subnigrum Lutz, S. rappae Py-Daniel, S. incrustatum Lutz, S. stellatum Gil-Azevedo, Figueiró & Maia-Herzog and Lutzsimulium pernigrum Lutz 1910. The highest larvae abundance and diversity were reported at the intermediate altitude site, Brejo da Lapa. Principal Components Analysis (PCA) revealed that L. pernigrum, S. stellatum and S. incrustatum were associated with the smaller breeding sites, the first two species being associated with sunny sites, while S. incrustatum occurred in sites with little sunlight.

A distribuição das taxocenoses de larvas de simulídeos (Diptera: Simuliidae) de diferentes altitudes no Parque Nacional de Itatiaia ( localizado no sudeste do estado do Rio de Janeiro, Brasil 44°34' - 44°42' W , 22°16' - 22°28' S ) foi investigada ao longo de quatro campanhas, cada uma em uma diferente estação do ano de 2003. Cada campanha foi composta de 60 amostras, obtidas a partir de "quadrats" de madeira de 30 x 30 cm, distribuídos através de quatro áreas: Taquaral, Véu da Noiva, Três Picos e Brejo da Lapa. Nas campanhas do inverno e da primavera, dois outros sítios, Alsene e Agulhas Negras, foram adicionados. Foram coletadas 3578 larvas e 292 pupas, sendo identificadas seis espécies: Simulium clavibranchium Lutz, S. subnigrum Lutz, S. rappae Py-Daniel, S. incrustatum Lutz, S. stellatum Gil-Azevedo, Figueiró & Maia-Herzog e Lutzsimulium pernigrum Lutz. As maiores abundância e diversidade foram encontradas no sítio de altura intermediária, o Brejo da Lapa. A análise de componentes principais (PCA) revelou que L. pernigrum, S. stellatum e S. incrustatum se mostraram associadas a rios de menor porte, com as duas primeiras espécies associadas a sítios com maior insolação e S. incrustatum com pouca insolação.

A new black fly isolate of Bacillus thuringiensis autoagglutinating strain highly toxic to Simulium pertinax (Kollar) (Diptera, Simuliidae) larvae

Formulations containing the entomopathogenic Bacillus thuringiensis serovar israelensis strain IPS-82 has been widely applied for mosquito control around the world. Strain IPS-82 is highly active against Aedes aegypti but less active against other well-known vectors such as Culex quinquefasciatus and Simulium spp. larvae. Eighteen strains of B. thuringiensis were isolated from Simulium pertinax larvae naturally occurring in rivers of Southeast Brazil with one demonstrating special toxic effects. Simulated field tests against S. pertinax larvae showed that the native Brazilian autoagglutinanting B. thuringiensis (LFB-FIOCRUZ 1035) has an LC50 at least 25 times lower than the standard IPS-82 strain. The same bacterial preparation was also tested against Ae. aegypti larvae in laboratory trials and the LC50 values obtained with LFB-FIOCRUZ 1035 were at least three times lower than the one for the IPS 82 strain. The results indicate that this strain is more toxic than the standard B. thuringiensis serovar israelensis (H14) in the two Dipteran species tested. It is noteworthy that differences between LC50 values were more pronounced in S. pertinax larvae, the source of the original isolation.

A bioassay method for black flies (Diptera: Simuliidae) using larvicides

Esta nota apresenta um método alternativo para bioensaios com larvas de simulídeos, com que se espera proporcionar aos pesquisadores uma ferramenta mais simples, porém igualmente efetiva para a obtenção de dados referentes à eficácia de larvicidas.