Aedes albopictus colonies from different geographic origins differ in their sleep and activity levels but not in the time of peak activity.

Mosquitoes occupy a wide range of habitats where they experience various environmental conditions. The ability of some species, such as the tiger mosquito, Aedes albopictus, to adapt to local conditions certainly contributes to their invasive success. Among traits that remain to be examined, mosquitoes' ability to time their activity with that of the local host population has been suggested to be of significant epidemiological importance. However, whether different populations display heritable differences in their chronotype has not been examined. Here, we compared laboratory strains originating from 8 populations from 3 continents, monitored their spontaneous locomotor activity patterns, and analyzed their sleep-like states. Overall, all strains showed conserved diurnal activity concentrated in the hours preceding the crepuscule. Similarly, they all showed increased sleep levels during the morning and night hours. However, we observed strain-specific differences in the activity levels at each phase of the day. We also observed differences in the fraction of time that each strain spends in a sleep-like state, explained by variations in the sleep architecture across strains. Human population density and the latitude of the site of geographic origin of the tested strain showed significant effects on sleep and activity patterns. Altogether, these results suggest that Ae. albopictus mosquitoes adapt to local environmental conditions via heritable adaptations of their chronotype.

RNA interference to combat the Asian tiger mosquito in Europe: A pathway from design of an innovative vector control tool to its application.

The Asian tiger mosquito Aedes albopictus is currently spreading across Europe, facilitated by climate change and global transportation. It is a vector of arboviruses causing human diseases such as chikungunya, dengue hemorrhagic fever and Zika fever. For the majority of these diseases, no vaccines or therapeutics are available. Options for the control of Ae. albopictus are limited by European regulations introduced to protect biodiversity by restricting or phasing out the use of pesticides, genetically modified organisms (GMOs) or products of genome editing. Alternative solutions are thus urgently needed to avoid a future scenario in which Europe faces a choice between prioritizing human health or biodiversity when it comes to Aedes-vectored pathogens. To ensure regulatory compliance and public acceptance, these solutions should preferably not be based on chemicals or GMOs and must be cost-efficient and specific. The present review aims to synthesize available evidence on RNAi-based mosquito vector control and its potential for application in the European Union. The recent literature has identified some potential target sites in Ae. albopictus and formulations for delivery. However, we found little information concerning non-target effects on the environment or human health, on social aspects, regulatory frameworks, or on management perspectives. We propose optimal designs for RNAi-based vector control tools against Ae. albopictus (target product profiles), discuss their efficacy and reflect on potential risks to environmental health and the importance of societal aspects. The roadmap from design to application will provide readers with a comprehensive perspective on the application of emerging RNAi-based vector control tools for the suppression of Ae. albopictus populations with special focus on Europe.

Evaluation of Hydrogen Peroxide Fumigation and Heat Treatment for Standard Emergency Arthropod Inactivation in BSL-3 Insectaries.

Climate change and global movements of people and goods have accelerated the spread of invasive species, including insects that vector infectious diseases, which threaten the health of more than half of the world's population. Increasing research efforts to control these diseases include the study of vector - pathogen interactions, involving the handling of pathogen-infected vector insects under biosafety level (BSL) 2 and 3 conditions. Like microbiology BSL-3 laboratories, BSL-3 insectaries are usually subjected to fixed-term or emergency room decontamination using recognized methods such as hydrogen peroxide (H2O2) or formaldehyde fumigation. While these procedures have been standardized and approved for the inactivation of diverse pathogens on surfaces, to date, there are no current standards for effective room-wide inactivation of insects in BSL-3 facilities in case of an emergency such as the accidental release of a large number of infected vectors. As H2O2 is often used for standard room decontamination in BSL-3 facilities, we evaluated H2O2 fumigation as a potential standard method for the safe, room-wide deactivation of insects in BSL-3 insectaries in comparison to heat treatment. To account for physiological diversity in vector insect species, six species from three different orders were tested. For the H2O2 fumigation we observed a strong but also varying resilience across all species. Lethal exposure time for the tested dipterans ranged from nine to more than 24 h. Furthermore, the coleopteran, Tribolium castaneum, did not respond to continuous H2O2 exposure for 48 h under standard room decontamination conditions. In contrast, temperatures of 50°C effectively killed all the tested species within 2 to 10 min. The response to lower temperatures (40-48°C) again showed a strong variation between species. In summary, results suggest that H2O2 fumigation, especially in cases where a gas generator is part of the laboratory equipment, may be used for the inactivation of selected species but is not suitable as a general emergency insect inactivation method under normal room decontamination conditions. In contrast, heat treatment at 48 to 50°C has the potential to be developed as an approved standard procedure for the effective inactivation of insects in BSL-3 facilities.

Temperature and Sugar Feeding Effects on the Activity of a Laboratory Strain of Aedes aegypti.

Aedes aegypti is an invasive mosquito species that is expected to expand its global distribution through climate change. As poikilotherms, mosquitoes are greatly affected by the temperature of the environment which can impact host-seeking, blood-feeding, and flight activity as well as survival and ability to transmit pathogens. However, an important aspect of mosquito biology on which the effect of temperature has not been investigated is water and sugar-feeding and how access to a sugar source might affect the insect's activity and survival under different thermal conditions. To close this knowledge gap, we relied on actometer experiments to study the activity of both female and male Ae. aegypti at 20 °C, 25 °C, and 30 °C, providing either water or 10% sucrose to the insects. We then measured the total carbohydrate contents of alive mosquitoes using the anthrone protocol. Survival was assessed and compared between all groups. Results from this study will inform on the thermal biology of Ae. aegypti mosquitoes and how access to sugar affects their activity.

Lipid metabolism in insect disease vectors.

More than a third of the world population is at constant risk of contracting some insect-transmitted disease, such as Dengue fever, Zika virus disease, malaria, Chagas' disease, African trypanosomiasis, and others. Independent of the life cycle of the pathogen causing the disease, the insect vector hematophagous habit is a common and crucial trait for the transmission of all these diseases. This lifestyle is unique, as hematophagous insects feed on blood, a diet that is rich in protein but relatively poor in lipids and carbohydrates, in huge amounts and low frequency. Another unique feature of these insects is that blood meal triggers essential metabolic processes, as molting and oogenesis and, in this way, regulates the expression of various genes that are involved in these events. In this paper, we review current knowledge of the physiology and biochemistry of lipid metabolism in insect disease vectors, comparing with classical models whenever possible. We address lipid digestion and absorption, hemolymphatic transport, and lipid storage by the fat body and ovary. In this context, both de novo fatty acid and triacylglycerol synthesis are discussed, including the related fatty acid activation process and the intracellular lipid binding proteins. As lipids are stored in order to be mobilized later on, e.g. for flight activity or survivorship, lipolysis and ß-oxidation are also considered. All these events need to be finely regulated, and the role of hormones in this control is summarized. Finally, we also review information about infection, when vector insect physiology is affected, and there is a crosstalk between its immune system and lipid metabolism. There is not abundant information about lipid metabolism in vector insects, and significant current gaps in the field are indicated, as well as questions to be answered in the future.

Effect of elevated CO2 and O3 on phytohormone-mediated plant resistance to vector insects and insect-borne plant viruses.

Climatic variations are becoming important limiting factors for agriculture productivity, as they not only directly affect the plant net primary productivity but can also modulate the outbreak of plant diseases and pests. Elevated CO2 and O3 are two important climatic factors that have been widely studied before. Elevated CO2 or O3 alters the host plant physiology and affects the vector insects and plant viruses via bottom-up effects of the host plants. Many studies have shown that elevated CO2 or O3 decreases the plant nitrogen content, which modulates the characteristics of vector insects. Recent evidence also reveals that hormone-dependent signaling pathways play a critical role in regulating the response of insects and plant viruses to elevated CO2 or O3. In the current review, we describe how elevated CO2 or O3 affects the vector insects and plant viruses by altering the SA and JA signaling pathways. We also discuss how changes in the feeding behavior of vector insects or the occurrence of plant viruses affects the interactions between vector insects and plant viruses under elevated CO2 or O3. We suggest that new insights into the upstream network that regulates hormone signaling and top-down effects of natural enemies would provide a comprehensive understanding of the complex interactions taking place under elevated CO2 or O3.

Odor, Not Performance, Dictates Bemisia tabaci's Selection between Healthy and Virus Infected Plants.

Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this "mother-knows-best" hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with "mother-knows-best" hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants.

Evaluation of triatomines infestation occurrence in home environments in the city of Taua-Ce, 2012 / Avaliação da ocorrência de infestação por triatomíneos em ambientes domiciliares no município de Tauá-Ce, 2012 / Evaluación de la ocurrencia de infestación por triatominos en ambientes domiciliarios en el municipio de Tauá-Ce, 2012

Background and Objectives: Triatomines are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease, a parasitic disease that affects mammals and humans. The destruction or transformation of natural ecotopes has intensified, resulting in the invasion of triatomines in households, bringing risks to the population. Thus, the objective of the study was to carry out a data survey on triatomine infestation in the countryside of the city of TauaCe, in 2012. Methods: This is a descriptive/exploratory study of a quantitative nature, where the Secondary data were obtained from the Municipal Health Department (Endemic Nucleus). Results: The percentage of infestation in the 15 locations studied was 26.1%, with the most affected locations being: Sítio Central do Incra 50%, Fazenda Brôco 18.2%, Jordão 16.7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37.5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17.4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41.2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33.3%, Iparana 9.1% and Cachoeira do Celso 16.7%. Conclusion: The study showed that there is a significant rate of triatomine infestation in the home environment, which represents a great risk to the health of the population of Taua. Therefore, a more frequent entomological control is suggested, going beyond the period of campaigns for a better monitoring of the occurrence of these insects in the area.(AU)

Justificativa e Objetivos: Triatomíneos são vetores de Trypanosoma cruzi, agente etiológico da doença de Chagas, parasitose que atinge mamíferos e humanos. A destruição ou transformação dos ecótopos naturais tem se intensificado, resultando na invasão de triatomíneos em domicílios trazendo riscos a população. Diante do exposto, o objetivo do estudo foi realizar um levantamento de dados sobre a infestação de triatomíneos em localidades do interior do município de Tauá-Ce, em 2012. Métodos: Trata-se de um estudo descritivo/exploratório de natureza quantitativa, onde os dados secundários foram obtidos junto à Secretaria de Saúde (Núcleo de Endemias) do município. Resultados: O percentual de infestação nas 15 localidades estudadas foi de 26,1%, sendo as localidades mais afetadas: Sítio Central do Incra 50%, Fazenda Brôco 18,2%, Jordão 16,7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37,5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17,4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41,2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33,3%, Iparana 9,1% e Cachoeira do Celso 16,7%. Conclusão: O estudo mostrou que há um expressivo índice de infestação triatomínica em ambiente domiciliar, o que representa um grande risco a saúde da população tauaense. Sendo assim, sugere-se um controle entomológico mais frequente, ultrapassando o período de campanhas para um melhor acompanhamento da ocorrência desses insetos na região.(AU)

Justificación y Objetivos: Los triatomíneos son vectores de Trypanosoma cruzi, agente etiológico de la enfermedad de Chagas, parasitosis que afecta a mamíferos y humanos. La destrucción o transformación de los ecótopos naturales se ha intensificado, resultando en la invasión de triatomíneos en domicilios trayendo riesgos a la población. Ante lo expuesto, el objetivo del estudio fue realizar un levantamiento de datos sobre la infestación de triatomíneos en localidades del interior del municipio de Tauá-Ce, en 2012. Métodos: Se trata de un estudio descriptivo/exploratorio de naturaleza cuantitativa, donde los datos secundarios fueron obtenidos junto a la Secretaría de Salud (Núcleo de Endemias) del municipio. Resultados: El porcentaje de infestación en las 15 localidades estudiadas fue de 26,1%, siendo las localidades más afectadas: Sítio Central do Incra 50%, Fazenda Brôco 18,2%, Jordão 16,7%, Fazenda Bom Lugar 0%, Fazenda Riacho do Mato 40%, Fazenda Cearauai 37,5%, Sítio Riacho do Mato 30%, Fazenda Cedro 17,4%, Cachoeirinha 27%, Fazenda Várzea do Feijão 24%, Cachoeira do Júlio 41,2%, Fazenda Mutuquinha 9,4%, Sítio Várzea Grande 33,3%, Iparana 9,1% e Cachoeira do Celso 16,7%. Conclusión: El estudio mostró que hay un expresivo índice de infestación triatomínica en ambiente domiciliar, lo que representa un gran riesgo para la salud de la población tauaense. Siendo así, se sugiere un control entomológico más frecuente, superando el período de campañas para un mejor seguimiento de la ocurrencia de esos insectos en la región.(AU)

Rhodnius prolixus smells repellents: Behavioural evidence and test of present and potential compounds inducing repellency in Chagas disease vectors.

Insect repellents are known since many decades ago and constitute a major tool for personal protection against the biting of mosquitoes. Despite their wide use, the understanding of why and how repellents repel is relatively recent. In particular, the question about to what extent insects other than mosquitoes are repulsed by repellents remains open. We developed a series of bioassays aimed to test the performance of well established as well as potential repellent molecules on the Chagas disease vector Rhodnius prolixus. Besides testing their ability to prevent biting, we tested the way in which they act, i.e., by obstructing the detection of attractive odours or by themselves. By using three different experimental protocols (host-biting, open-loop orientation to odours and heat-triggered proboscis extension response) we show that DEET repels bugs both in the presence and in the absence of host-associated odours but only at the highest quantities tested. Piperidine was effective with or without a host and icaridine only repelled in the absence of a living host. Three other molecules recently proposed as potential repellents due to their affinity to the Ir40a(+) receptor (which is also activated by DEET) did not evoke significant repellency. Our work provides novel experimental tools and sheds light on the mechanism behind repellency in haematophagous bugs.

Factores asociados a la infestación domiciliaria por Aedes aegypti en el corregimiento el Manzanillo, municipio de Itagüí (Antioquia) año 2015 / Ae. aegypti home infestation related factors in the township of Manzanillo, in the City of Itagui (Antioquia), 2015 / Fatores associados na infestação domiciliaria por ae. aegypti na corregedoria El manzanillo, Prefeitura de Itagüí (Antioquia), 2015

Resumen Introducción: El Ae. aegypti es una especie adaptada a ambientes urbanos, es el vector de varias enfermedades virales, entre ellas el dengue, zika y chikungunya que es considerada la más importante debido a las altas tasas de morbilidad y mortalidad. Objetivo: Determinar los factores demográficos, socioeconómicos, ambientales y de conocimientos y costumbres, asociados a la infestación domiciliaria por Ae. aegypti, en el corregimiento El Manzanillo del municipio de Itagüí en el año 2015. Metodología: Se realizó un estudio cuantitativo de tipo observacional y transversal; entre octubre y diciembre del 2015. La población de estudio estuvo conformada por las viviendas de las ocho veredas del corregimiento El Manzanillo del municipio de Itagüí; en las cuales se realizó una encuesta sobre los factores demográficos, socioeconómicos, ambientales, de conocimientos y costumbres, además de la medición de índices Aedicos con la técnica (LIRAa). Resultados: Se analizaron 400 encuestas. La mayoría de personas encuestadas eran mujeres entre los 18 y 33 años, que convivían en unión libre, afiliadas al régimen contributivo. La mayor proporción de viviendas eran propias entre los estratos 1 y 2, en las cuales habitaban entre 1 y 4 personas. Las personas encuestadas no tenían mayor conocimiento sobre el dengue o participación en campañas de prevención. De las ocho veredas El Ajizal presentó los índices aédicos más altos. Los principales factores potencialmente asociados a la infestación domiciliaria por Ae. aegypti fueron vivir cerca de un sitio de disposición de inservibles, almacenamiento de agua en la vivienda y el control de agua almacenada Conclusiones: Se requiere concertar programas de educación comunitaria con participación activa y consciente de los habitantes con énfasis en medidas que reduzcan la infestación de las viviendas

Abstract Introduction: Ae. Aegypti is a species adapted to urban environments. It is the vector of several viral diseases including dengue, Zika and chikungunya. Objective: Determine demographic, social-ambiental and environmental factors and knowledge and custom factors related to Ae. aegypti home infestation, in the township of Manzanillo, in the City of Itagui in 2015. Methodology: Observational quantitative study from October to December 2015. The study population was formed by houses in the 8 rural areas of the township. A survey was conducted regarding demographic factors, social-economic factors, environmental factors, knowledge and custom factors and Aedic measurement using (LIRAa) technique. Results: 400 surveys were analyzed. Most of the people interview were women of ages ranging from 18 to 33, who cohabited with their partners, and were members of contributive healthcare scheme. The largest part of the houses belonged to homeowners ranging from stratum 1 to stratum 2 which were inhabited by 1 to 4 people. The people interview did not have much knowledge regarding dengue or participating in prevention campaigns. Of the eight rural areas, El Ajizal had the highest aedic indexes. The principal factors were potentially related to Ae. aegypti home infestation were living close to places where people dump garbage, storing water in the house and poor control of standing water. Conclusions: It is necessary to arrange Community Education programs with inhabitants' active aware participation with an emphasis on measures that reduce home infestation.

Resumo Introdução: Ae. aegypti é una espécie adaptada nos ambientes urbanos, é o vector de várias doenças virais, entre elas o dengue, zika e chikungunya. Objetivo: Determinar os fatores demográficos, socioeconómicos, ambientais e de conhecimentos e costumes, associados na infestação domiciliaria por Ae. aegypti, na corregedoria El Manzanillo da prefeitura de Itagüí no ano 2015. Metodologia: Estudo quantitativo de tipo observacional entre outubro e dezembro do 2015. A população de estudo esteve conformada pelas vivendas das oito vilas de corregedoria. Se realizou uma enquete sobre os fatores demográficos, socioeconómicos, ambientais, de conhecimentos e costumes e medição de índices Aedicos com a técnica (LIRAa). Resultados: Se analisaram 400 enquetes. A maioria de pessoas inqueridas eram mulheres entre os 18 e 33 anos, que conviviam em união livre, imputadas no regime contributivo. A maior proporção de vivendas era própria entre os estratos 1 e 2, nas quais habitavam entre 1 e 4 pessoas. As pessoas interpeladas não tinham maior conhecimento sobre o dengue ou participação em campanhas de prevenção. Das oito vilas El Ajizal apresentou os índices aédicos mais altos. O principal fator potencialmente associado na infestação domiciliaria por Ae. aegypti foi viver perto dum sitio de disposição de inservíveis, armazenagem de agua na vivenda e o controle de agua armazenada. Conclusões: Se requer concertar programas de educação comunitária com participação ativa e consciente dos habitantes com ênfase em medidas que reduzam a infestação das vivendas

Caracterização de vírus inseridos nos genomas de culicídeos vetores de patógenos

Elementos virais endogenizados (EVEs) são sequências de origem viral que se integraram no genoma do seu hospedeiro. Nos últimos anos, uma quantidade crescente de estudos tem demonstrado que EVEs podem adquirir uma variedade de novas funções, modificando ou originando novos genes e redes regulatórias. Mosquitos são artrópodes vetores de vários arbovírus (vírus transmitidos por Artrópodes) responsáveis por causar infecções nas populações humanas: como o vírus da dengue, chikungunya e Zika. Arbovírus possuem uma forte associação com algumas espécies de mosquitos, o que sugere que estes tenham co-evoluído com culicídeos há alguns milhares de anos. A disponibilidade de dados genômicos de culicídeos nos permite compreender as relações evolutivas e o impacto dos EVEs no genoma desses insetos. Dessa maneira, este projeto teve como objetivo caracterizar a diversidade de EVEs presentes nos genomas de 36 espécies de culicídeos, os quais representam, em sua maioria, espécies de importância médica/epidemiológica, bem como identificar possíveis impactos nestes genomas. Foram identificadas 1998 sequências de origem viral no material genético de 36 espécies de culicídeos, representando um total de 27 famílias virais. As famílias Rhabdoviridae, Chuviridae e Flaviviridae apresentam a maior quantidade de elementos endogenizados, com 597, 459 e 228 elementos, respectivamente. Foi possível relacionar dois possíveis eventos evolutivos atrelados a EVEs da família Chuviridae, a possível origem de um novo retrovírus, fruto da hibridização de retroelementos Pao com o gene que é traduzido em glicoproteína de Chuvirus, e um possível mecanismo antiviral a partir de glicoproteínas endogenizadas. Estes resultados refletem uma grande diversidade de vírus integrados ao genoma de culicídeos, e levantam questões sobre a importância desses elementos nos genomas estudados.

Vigilância entomológica de arbovírus de importância médica em mosquitos dos gêneros aedes e culex

Mosquitos do gênero Aedes são os principais vetores dos vírus Dengue (DENV), Zika (ZIKV) e Chikungunya (CHIKV). Além destes mosquitos, estudos demonstraram em condições de laboratório, a competência vetorial de Culex quinquefasciatus em transmitir ZIKV. A vigilância entomológica é uma ferramenta importante para o monitoramento de vetores, através de vários indicadores de presença de mosquitos, e pode também ser realizada a partir da detecção do agente patogênico em seu vetor. Diante do exposto, este trabalho avaliou a circulação de DENV, ZIKV e CHIKV em mosquitos dos gêneros Aedes e Culex coletados na Região Metropolitana de Recife (RMR) . Para isto, os mosquitos foram coletados no período de 2015 a 2017 por meio de aspiradores, separados em grupos (pools) por espécie, sexo e estado alimentar. Os pools de fêmeas foram submetidos à extração de RNA, RT-PCR e RT-qPCR. Adicionalmente, foi feito isolamento viral a partir das amostras positivas em culturas de células C6/36, seguido de sequenciamento de nova geração dessas amostras. No total, foram coletadas 6.227 fêmeas, das quais 51,75% foram da espécie A. aegypti (497 pools), 0,03% de A. albopictus (1 pool), 0,01% de A. taeniorhynchus (1 pool), 0,17% de A. scapularis (1 pool) e 48,04% de C. quinquefasciatus (549 pools). No total foram detectados 19 pools positivos para DENV (sorotipos 2 e 4), 194 para ZIKV e seis para CHIKV. Em relação à MIR para ZIKV, a taxa encontrada variou de 18,59 a 1.000, para DENV variou de 1,70 a 15,75 e para CHIKV a MIR encontrada foi de 2,75. Três amostras para DENV e uma para ZIKV apresentaram efeito citopático após inoculação em células C6/36. Um total de oito genomas de ZIKV foram sequenciados, com cobertura que variou de 24% a 100%. A investigação realizada permitiu acompanhar a dinâmica de infecção vetorial e demonstrou que mesmo após a epidemia, ainda foi possível detectar mosquitos positivos na RMR .

Ecology of phlebotomines (Diptera, Psychodidae) in rural foci of leishmaniasis in tropical Brazil / Ecologia de flebotomíneos (Diptera, Psychodidae) em foco rural de leishmaniose no Brasil tropical

INTRODUCTION: This work aimed to study the community structure of sandflies, with regard to the richness, constancy, abundance, and monthly frequency of the species with a focus on the transmission of leishmaniasis. METHODS: The study was conducted in the rural villages of Bom Jardim and Santa Maria, situated on the edge of a tropical rain forest in the municipality of São Jose de Ribamar, Maranhão, Brazil. The phlebotomines were captured in the intradomiciles and peridomiciles of each village, with Centers for Disease Control (CDC) light traps set in 10 homes in each village, for 1 year, once a month, from 18h to 6h. RESULTS: We collected 1,378 individuals of 16 sandfly species. The capture success rate was higher in Bom Jardim (0.61 specimens/hour/trap) than that of Santa Maria (0.35/specimens/hour/trap). The sandflies were more abundant in the peridomiciles (86.1%) and in the rainy season (77%). Five species were considered constants (occurring in more than 50% of samples), 5 accessory (25%-50%), and 6 accidental (<25%). The most abundant species were Lutzomyia longipalpis (59.7%) and L whitmani (28%). The permutation analysis showed differences between the species composition of the villages and no separation between the intradomicile and peridomicile of each village. The species that most contributed to the dissimilarity between the light traps of the 2 villages were L. longipalpis, L. whitmani, and L. evandroi, contributing to 80.8% of the variation among groups. CONCLUSIONS: The high level of richness and abundance of species and the presence of competent vectors throughout the year and around houses justify the occurrence of leishmaniasis cases reported in the area.

INTRODUÇÃO: Este trabalho teve como objetivo estudar a estrutura da comunidade de flebotomíneos, dando a conhecer a riqueza, constância, abundância e a frequência mensal das espécies em foco de transmissão de leishmaniose. MÉTODOS: O estudo foi realizado nas localidades rurais de Bom Jardim e Santa Maria, situadas às margens de uma mata ombrófila infestada por esses insetos, no município de São José de Ribamar, Maranhão, Brasil. Os flebotomíneos foram capturados no intra e peridomicílio de cada vila, com 10 armadilhas luminosas tipo CDC em cada vila, durante um ano, uma vez por mês, das 18h às 6h. RESULTADOS: Foram capturados 1.378 indivíduos de dezesseis espécies e o esforço de captura foi maior em Bom Jardim (0,61 indivíduos/hora/armadilha) que em Santa Maria (0,35). Os flebotomíneos prevaleceram no peridomicílio (86,1%) e na estação chuvosa (77%). Cinco espécies foram consideradas constantes (ocorreram em mais de 50% das coletas), cinco acessórias (25% e 50%) e seis acidentais (< 25%). As espécies mais abundantes foram Lutzomyia longipalpis (59,7%) e Lutzomyia whitmani (28%). Estatisticamente, detectou-se uma diferença na composição das espécies entre os povoados. As espécies que mais contribuíram para a dissimilaridade entre as armadilhas das duas vilas foram Lutzomyia longipalpis, Lutzomyia whitmani e Lutzomyia evandroi, com 80,8% de variação entre os grupos. CONCLUSÕES: A elevada riqueza e abundância de flebotomíneos e a presença de vetores competentes ao longo do ano, justificam a ocorrência de casos de leishmanioses relatados na área.