Effect of using forced and free oviposition methods to obtain eggs and larvae of Mansonia (Diptera: Culicidae) females from Rondonia, Brazil (western Amazon)

ABSTRACT Species of the genus Mansonia Blanchard are disease pathogen vectors in some regions of the world and can cause considerable inconvenience due to their bites when present in high numbers. However, little is known regarding their biology in Brazil. The objective of this work was to investigate some reproductive parameters of Mansonia from the western Brazilian Amazon. Females were captured in the field using human landing catches in rural areas of Porto Velho, Rondonia, Brazil. The mosquitoes were identified and separated into two groups for oviposition: forced, i.e., with wing removal, and free oviposition, without wing removal. Daily observations of oviposition and female survival were conducted until oviposition. The eggs and subsequent larvae were counted for fecundity and fertility evaluation, respectively. The species collected in this study were Mansonia amazonensis (Theobald), Mansonia humeralis Dyar & Knab and Mansonia titillans (Walker). The oviposition percentage for Ma. amazonensis was much lower than for Ma. humeralis and Ma. titillans. Forced oviposition resulted in a higher number of ovipositing females only for Ma. humeralis. Fecundity and fertility were not affected by the oviposition method. Egg and larval numbers were generally lower for Ma. amazonensis compared with the other species. Forced oviposition may be a tool to increase the number of ovipositing females depending on the Mansonia species studied in order to establish colonies in the laboratory.

Fauna of Culicidae in rural areas of Porto Velho and the first record of Mansonia (Mansonia) flaveola (Coquillet, 1906), for the state of Rondônia, Brazil / Fauna de Culicidae em áreas rurais de Porto Velho e primeiro registro de Mansonia (Mansonia) flaveola (Coquillet, 1906), para o estado de Rondônia, Brasil

INTRODUCTION: Knowledge concerning the fauna of Culicidae in the Brazilian Amazon States contributes to current understanding of the bionomics of the insects collected and makes it possible to observe changes in the fauna over time. METHODS: The Culicidae were captured with a BG-Sentinel® trap in extra-domiciliary area of two rural regions of Porto Velho in June and July of 2007 and 2008. RESULTS: A total of 10,695 Culicidae was collected, belonging to nine genera: Coquillettidia, Culex, Mansonia, Psorophora, Aedes, Aedeomyia, Anopheles, Uranotaenia and Wyeomyia. CONCLUSIONS: The presence of Mansonia (Mansonia) flaveola was recorded in the State of Rondônia for the first time.

INTRODUÇÃO: O conhecimento da fauna de culicídeos em estados da Amazônia Brasileira auxilia no conhecimento da bionomia dos insetos obtidos, além de possibilitar a observação de modificações da fauna ao decorrer do tempo. MÉTODOS: As capturas dos culicídeos foram realizadas em área extradomiciliar de duas zonas rurais de Porto Velho, durante junho e julho, nos anos de 2007 e 2008, com a armadilha BG-Sentinel®. RESULTADOs: Foram coletados 10.695 culicídeos, distribuídos em nove gêneros: Coquillettidia, Culex, Mansonia, Psorophora, Aedes, Aedeomyia, Anopheles, Uranotaenia e Wyeomyia. CONCLUSÕES: Foi registrada pela primeira vez no estado a presença de Mansonia (Mansonia) flaveola.

Nuevos registros de mosquitos (Diptera Culicidae) para el estado Bolívar, Venezuela: Dos de ellos nuevos para el país / New records of mosquitoes (Diptera Culicidae) for the state of Bolivar, Venezuela: Two of them new to the country

En el presente trabajo se hace referencia por primera vez para el estado Bolívar de diez y nueve especies de mosquitos (Diptera Culicidae), pertenecientes a diez (10) géneros: Anopheles, Chagasia, Culex, Aedes, Mansonia, Coquilletidia, Uranotaenia, Psorophora, Limatus y Wyeomyia, de las subfamilias Anophelinae y Culicinae. Dos de estas especies, son citadas por primera vez para Venezuela: Chagasia bonneae Root, 1927 y Chagasia ablusa Harbach, 2009.

First report of 19 Culicidae species (Diptera: Culicidae) from Bolivar State is made, belonging to 10 genera of Anophelinae and Culicinae: Anopheles, Chagasia, Culex, Aedes, Mansonia, Coquilletidia, Uranotaenia, Psorophora, Limatus and Wyeomyia. Chagasia bonneae Root, 1927 and Chagasia ablusa Harbach, 2009 are reported for the first time in Venezuela.

Culicinae mosquitoes in Sanandaj county, Kurdistan province, western Iran.

Background & objectives: This study aims at studying mosquito-borne diseases as the major public health threat in Iran. Sanandaj outskirts are considered suitable habitats for mosquito larvae. In view of scanty reports on mosquito-borne disease implementation in this area, a study was undertaken to determine the mosquito fauna and frequency of mosquito larvae at Sanandaj City. Methods: In order to study the mosquito (Diptera: Culicidae) fauna, the samples were collected from May to July 2009 using dipping and night catch methods in Sanandaj district, Kurdistan province, western Iran. Results: Three genera and 11 species of the Culicinae subfamily were identified—Aedes vexans Meigen, Ochlerotatus caspius s.l. Pallas (indicating new occurrence records for the province), Culex hortensis Ficalbi, Cx. pipiens Linnaeus, Cx. mimeticus Noe, Cx. theileri Theobald, Culiseta longiareolata Macquart, and Cs. subochrea Edwards. Interpretation & conclusion: Present study revealed that Ae. vexans and Ochlerotatus caspius s.l caught had not been previously recorded in Kurdistan province, highlighting the deficient knowledge of the fauna and distribution of Culicinae mosquitoes of this part of Iran.

Larvicidal activity of Copaifera reticulata ducke oil-resin against Culex quinquefasciatus Say (Diptera: Culicidae) / Atividade larvicida do óleo-resina de Copaifera reticulata sobre Culex quinquefasciatus Say (Diptera: Culicidae)

The appearance of resistance of Culex quinquefasciatus Say to chemical insecticides and the modification of the susceptibility of this mosquito to pyrethroid has stimulated studies on the activity of plants as alternative for its control. In this study, bioassays were carried out to verify the larvicidal activity of the oil-resin of Copaifera reticulata on C. quinquefasciatus. The bioassays were carried out with the oil dissolved in dimethylsulfoxide (DMSO), at the proportion of 0.4 ml of DMSO to 24.6 ml of distilled water. For each instar, the bioassays were carried out in plastic glasses with 100 ml solution using 20 larvae, wit four replications to adjust the lethal concentrations. The mortality observations were made after 48h exposure of the larvae to the solution. The control was carried out in distilled water and DMSO, with the same number of replications as the bioassays. The experiments were carried out in a biological chamber, controlled at 28 ± 1°C, 80 ± 5 percent relative humidity and 12h light. The larvae without movement were considered dead. The C. reticulata oil-resin demonstrated larvicide activity for all the C. quinquefasciatus instars. The LC50 found for the 1st, 2nd, 3rd and 4th larval instars were: 0.4, 0.9, 39 and 80 ppm, and the LC99 were 15, 15, 50 and 180 ppm, respectively.

A evolução de resistência de Culex quinquefasciatus Say aos inseticidas sintéticos e a modificação da suscetibilidade desse mosquito aos piretróides, estimularam estudos sobre a atividade de plantas inseticidas, como alternativa para o seu controle. Neste trabalho foram realizados ensaios biológicos para verificar a atividade larvicida do óleo-resina de Copaifera reticulata sobre C. quinquefasciatus. Para a realização dos bioensaios o óleo-resina foi solubilizado com dimetilsulfóxido (DMSO), na proporção de 0,4 ml do DMSO para 24,6 ml de água destilada. Para cada estádio, os bioensaios foram realizados em copos descartáveis, contendo 100 ml de solução na qual colocavam-se 20 larvas, com quatro réplicas para ajuste das concentrações letais. As leituras de mortalidade foram feitas após 48h de exposição das larvas à solução. O controle foi feito em água destilada e DMSO, com o mesmo número de réplicas dos bioensaios. Os experimentos foram realizados numa câmara biológica, climatizada a 28 ± 1°C, umidade relativa de 80 ± 5 por cento e fotofase de 12h e posteriormente, no campo. Foram consideradas mortas as larvas que não possuíam movimentos. O óleo-resina de C. reticulata demonstrou atividade larvicida para todos os estádios de C. quinquefasciatus. As LC50 encontradas para larvas de 1°, 2°, 3° e 4° estádios foram de 0,4; 0,9; 39 e 80 ppm, e as LC99 foram de 15; 15; 50 e 180 ppm, respectivamente.