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.

Larvicidal activity of Maytenus guianensis (Celastraceae) against Aedes aegypti (Diptera: Culicidae)

Abstract INTRODUCTION: Bioprospection of plant products is used to discover new insecticides. METHODS: The larvicidal activity of ethanolic extract and triterpene (tingenone B) from the bark of Maytenus guianensis and their effect on pupation and emergence were evaluated against Aedes aegypti. RESULTS: Crude extract LC50 was 11.3 ppm and caused ejection of the larvae intestine; tingenone B LC50 was 14.8 ppm. Pupation was reduced by 20% and 10%, respectively; however, the emergence was not affected. CONCLUSIONS: The crude bark extract exhibited a higher larvicidal effect against the vector.

Blood supplementation with vitamins increases the fertility of Anopheles darlingi (Diptera: culicidae)

Anopheles darlingi is one of the main vectors of human malaria in Brazil. Female mosquitoes use blood from vertebrates to produce their eggs and larvae. Blood composition, including vitamins, may alter fecundity and fertility, impacting mass production in the laboratory. Thus, the objective of this work was to evaluate the effect of blood supplementation with vitamins on the reproductive parameters of An. darlingi. Mosquito females were collected in a rural area of Porto Velho, and a blood meal was given in the field, adding different amounts of multivitamins in concentrations between 1 and 0.01%. The number of engorged mosquitoes and, subsequently, other variables such as survival up to oviposition, proportion of mosquitoes laying eggs, number of eggs and larvae produced were recorded. Engorgement, survival, and proportion of females laying eggs, as well as egg production, except in females supplemented with 1% of the multivitamin, were not altered by supplementation. However, the number of larvae produced increased significantly (about 20%) in females supplemented with 0.01% compared to control (no vitamins added). The present results suggest that general supplementation by vitamins increases the fertility of An. darlingi.

Insecticidal activity of Leptodactylus knudseni and Phyllomedusa vaillantii crude skin secretions against the mosquitoes Anopheles darlingi and Aedes aegypti

Mosquitoes are important vectors of several diseases, including malaria and dengue, and control measures are mostly performed using chemical insecticides. Unfortunately, mosquito resistance to commonly applied insecticides is widespread. Therefore, a prospection for new molecules with insecticidal activity based on Amazon biodiversity using the anurans Leptodactylus knudseni and Phyllomedusa vaillantii was performed against the mosquito species Anopheles darlingi and Aedes aegypti. The granular secretion from anuran skin was obtained by manual stimulation, and lethal concentrations(LCs) for larvicidal and adulticidal tests were calculated using concentrations from 1-100 ppm. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The calculated LC50 of L. knudseni skin secretions against An. darlingi was 0.15 and 0.2 ppm for adults and larvae, respectively, but much higher for Ae. aegypti, i.e., 19 and 38 ppm, respectively. Interestingly, the calculated LCs50 of P. vaillantii against both mosquito species in adults were similar, 1.8 and 2.1 ppm, respectively, but the LC50 for An. darlingi larvae was much lower (0.4 ppm) than for Ae aegypti (2.1 ppm). The present experiments indicate that skin secretions from L. knudseni and P. vaillantii contain bioactive molecules with potent insecticide activity. The isolation and characterization of skin secretions components will provide new insights for potential insecticidal molecules.

Copaifera multijuga ethanolic extracts, oil-resin, and its derivatives display larvicidal activity against Anopheles darlingi and Aedes aegypti (Diptera: Culicidae)

Copaifera spp. is a common tree species found in the tropical region of Latin America, popularly known as copaiba or pau-d'alho. Oil-resin from different Copaifera species and its components present several biological activities such as antimicrobial, anti-inflammatory, antioxidant and insecticidal, including larvicidal activity against mosquitoes. Thus, bark and leaf ethanolic extracts, oil-resin, essential oil and alepterolic acid from Copaifera multijuga Hayne, Fabaceae, were tested as larvicides against the main malaria vector in the north of Brazil, Anopheles darlingi and also Aedes aegypti, the dengue vector. A. darlingi larval mortality was significantly higher than A. aegypti for most tested compounds. Bark and leaf extracts resulted in lower Lethal Concentrations (LC50) values for A. darlingi, 3 and 13 ppm, respectively, while the essential oil provided the lowest LC50 value for A. aegypti, 18 ppm. Despite of that, the lowest LC values were from the alepterolic acid for both species, i.e. 0.9 and 0.7 ppm for A. darlingi and A. aegypti, respectively.

Diversity of Braconidae (Insecta, Hymenoptera) of the Parque Natural Municipal de Porto Velho, Rondonia, Brazil / Diversidade de Braconidae (Insecta, Hymenoptera) do Parque Natural Municipal de Porto Velho, Rondônia, Brasil

Braconidae is a highly diversified family of Hymenoptera and usually known by their role in biological control both in agricultural and natural ecosystems. Despite of that, little is known about its diversity in the Amazon region. The present work inventoried the braconid fauna of an Open Ombrophylous Forest with Palm Trees of the Parque Natural Municipal de Porto Velho, RO. Insects were collect from June/2008 to May/2009 using six Malaise traps in different parts of the reserve. A total of 377 wasps were captured, 17 subfamilies and 56 genera identified. Braconinae, Microgastrinae, Doryctinae and Rogadinae subfamilies were very abundant, and also the genera Aleiodes, Bracon, Capitonius, Compsobracon, Heterospilus, Hymenochaonia, Opius, Pedinotus, Rogas and Stantonia. The calculated Shannon diversity index was 2.15 and 3.3 for subfamily and genera, respectively, which were, generally, higher than the values found for other regions in Brazil. Generally, parasitoids were more abundant during the rainy season. The present work contributes with new genera records and faunistic data of Braconidae in Rondonia State, western Amazon.

Braconidae é uma família altamente diversificada dentro da ordem Hymenoptera, possuindo grande importância no controle biológico tanto em sistemas agrícolas como em sistemas naturais. Contudo, a diversidade do grupo ainda é pouco conhecida para a região amazônica. Neste sentido, o presente estudo vem contribuir para este conhecimento através do inventariamento da assembléia de braconídeos do Parque Natural Municipal de Porto Velho, Rondônia. As coletas foram realizadas pelo período de um ano, utilizando seis armadilhas Malaise em uma área de Floresta Ombrófila Aberta com palmeiras. Foram coletados 377 espécimes, identificados em 17 subfamílias e 56 gêneros. As subfamílias Braconinae, Microgastrinae, Doryctinae e Rogadinae foram consideradas muito abundantes, assim como os gêneros: Aleiodes, Bracon, Capitonius, Compsobracon, Heterospilus, Hymenochaonia, Opius, Pedinotus, Rogas e Stantonia. O índice de diversidade calculado para as subfamílias (H = 2,15) e gêneros (H = 3,3) coletados neste trabalho foi maior do que o encontrado em alguns trabalhos em outras regiões do Brasil. A abundância desses insetos durante a estação chuvosa foi significativamente maior do que na seca. Este trabalho contribui com novos dados faunísticos sobre Braconidae para o Estado de Rondônia.

Evaluation of larvicidal activity of the methanolic extracts of Piper alatabaccum branches and P. tuberculatum leaves and compounds isolated against Anopheles darlingi

Piper is a notable genus among Piperaceae due to their secondary metabolites such as lignans, amides, esters and long chain fatty acids used as anti-herbivore defenses with comparable effects of pyrethroids, that holds a promise in insect control, including malaria vectors such as Anopheles darlingi, the main vector in the North of Brazil. Methanolic extracts of Piper tuberculatum Jacq., Piperaceae, and P. alatabaccum Trel. & Yunck., Piperaceae, and some isolated compounds, i.e, 3,4,5-trimetoxy-dihydrocinamic acid, dihydropiplartine; piplartine, piplartine-dihydropiplartine and 5,5',7-trimetoxy-3',4'-metilenodioxiflavone were tested as larvicides against A. darlingi. The Lethal Concentrations (LC50 and LC90) of methanolic extracts were 194 and 333 ppm for P. tuberculatum and 235 and 401 ppm for P. alatabacum, respectively. Isolated compounds had lower LC values, e.g. the LC50 and LC90 of the piplartine-dihidropiplartine isolated from both plant species was 40 and 79 ppm, respectively.

Cerambycidae (Insecta: Coleoptera) of the Parque Natural Municipal de Porto Velho, Rondônia, Western Amazon, Brazil / Cerambycidae (Insecta: Coleoptera) do Parque Natural Municipal de Porto Velho, Rondônia, Amazônia Ocidental, Brasil

Cerambycidae is one of the largest families of beetles and it is estimated that there are about 25,000 species of longhorned beetles in the world. However, little is known about the distribution of many species in some regions, including the Amazon. The longhorned beetles are indispensable in the ecological chain, contributing mostly to the recycling of dead wood in forest. The present study is an inventory of the Cerambycidae of the Parque Natural Municipal de Porto Velho, Rondônia, Brazil. Insects were sampled from June 2008 to May 2009 using Malaise and light traps. A total of 61 species were identified, of which 33 are new records for Rondônia and one for Amazon region, i.e., Anisopodus melzeri Gilmour, 1965.

Cerambycidae representa uma das maiores famílias de besouros e estima-se que existam cerca de 25000 espécies de Cerambycidae no mundo. No entanto, pouco se conhece sobre a distribuição geográfica de muitas espécies, conseqüência da escassez de coletas em algumas regiões, como a Amazônia. Os cerambicídeos desempenham um papel imprescindível na cadeia ecológica, contribuindo na reciclagem de madeira morta na floresta. Neste estudo, é apresentado um inventário de Cerambycidae do Parque Natural Municipal de Porto Velho, Rondônia, Brasil. As coletas foram realizadas durante o período de junho de 2008 a maio de 2009 utilizando as armadilhas Malaise e luminosa (modelo Luiz de Queiroz). Um total de 61 espécies foram identificadas, das quais 33 são novos registros para Rondônia e um para a região amazônica Anisopodus melzeri Gilmour, 1965.

Species structure of sand fly (Diptera: Psychodidae) fauna in the Brazilian western Amazon

We surveyed areas of the state of Rondônia in western Amazon for phlebotomine, which are potential vectors of leishmaniasis. A total of 5,998 specimens were captured, resulting in the identification of 48 species within the Lutzomyia (99.98 percent) and Brumptomyia (0.02 percent) genera. The predominant species was Lutzomyia davisi, followed by Lutzomyia umbratilis, Lutzomyia llanosmartinsi, Lutzomyia c. carrerai, Lutzomyia dendrophyla, Lutzomyia nevesi and Lutzomyia whitmani. All sand flies identified as vectors for cutaneous leishmaniasis in Brazil, i.e., Lu. davisi, Lu. umbratilis, Lu. c. carrerai and Lu. whitmani, were found in the surveyed areas.

Malária e aspectos hematológicos em moradores da área de influência dos futuros reservatórios das hidrelétricas de Santo Antônio e Jirau, Rondônia, Brasil / Malaria and hematological aspects among residents to be impacted by reservoirs for the Santo Antônio and Jirau Hydroelectric Power Stations, Rondônia State, Brazil

Em Rondônia, prevê-se a construção de mais duas usinas hidrelétricas (UHE) no rio Madeira, a montante da cidade de Porto Velho, Rondônia, Brasil (de Santo Antônio e Jirau). O objetivo deste trabalho foi analisar a prevalência da malária antes do início da implantação das obras civis e fazer considerações sobre os impactos da doença com o ingresso de milhares de trabalhadores e agregados atraídos pelas oportunidades de emprego e comércio. Os resultados obtidos mostram que a malária se faz presente em toda região, em variados graus de prevalência. Além disso, a existência de potenciais portadores assintomáticos de malária entre a população nativa pode ter relevância epidemiológica e deve ser considerada nos programas de controle da malária, vinda tanto das autoridades públicas quanto das empresas responsáveis pela instalação das UHE, visando o diagnóstico e tratamento precoce, controle vetorial, abastecimento de água e aplicação de infra-estrutura nos centros urbanos.

In Rondônia State, Brazil, two new hydroelectric plants, Santo Antônio and Jirau, are scheduled for construction on the Madeira River, upriver from the State capital, Porto Velho. The current study analyzes malaria prevalence before the construction and provides information on the possible impacts of malaria burden related to the influx of thousands of persons attracted by direct and indirect employment opportunities. According to the findings, malaria is present throughout the region, with varying prevalence rates. The existence of potential asymptomatic malaria carriers among the local population may be epidemiologically relevant and should be considered in the malaria control programs organized by public authorities and companies responsible for building the power plants, aimed at early diagnosis and treatment, vector control, water supply, and infrastructure in the urban areas.