Dissertationen zum Thema „Simulium (Diptera: Simuliidae)“

Orientadores: Carlos Fernando S. Andrade, Shirlei M. Recco-Pimentel
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Foram realizados estudos cromossômicos em seis populações de Simulium (Chirostilbia) pertinax do Brasil. Pela análise dos gânglios cerebrais larvais da população de Morungaba, SP verificou-se que a espécie apresenta um cariótipo com 2n=6 cromossomos, sendo dois pares metacêntricos e um par submetacêntrico. Com base em metodologia padronizada para a família Simuliidae, foram elaborados os mapas dos cromossomos politênicos de glândulas salivares larvais. Os cromos somos politênicos apresentaram constância morfológica no seu padrão de bandas. Não foi registrada qualquer constrição importante e regiões assinápticas foram raras. Também, não foram observados cromossomos B nem segmento diferencial do sexo. A comparação do padrão de bandas dos cromossomos politênicos com aquele "standard" do subgênero Simulium mostrou uma semelhança de cerca de 63% para várias regiões nos seis braços cromossômicos. Além da população de Morungaba (n=1O2), foram analisadas mais cinco populações de S. pertinax coletadas nos estados do Paraná (Tibaji, n=13), Rio Grande do Sul (Nova Petrópolis, n=14), Rio de Janeiro (Muriqui, n=40) e São Paulo (Barra do Una, n=38; e llhabela, n=48). Foram feitas comparações dos cromos somos politênicos dentro e entre seis populações. Os cromossomos politênicos apresentaram pareamento dos homólogos e conspícuas regiões centroméricas. As características morfológicas dos cromossomos politênicos, como centrômeros, marcadores universais, região organizadora nucleolar (NOR) e padrão de bandas, não apresentaram variação apreciável dentro e entre as populações, exceto um polimorfismo de expressão, uma região organizadora nucleolar secundária (NOR 2°) em um indivíduo. Apesar de quatro das populações apresentarem características bioecológicas diferentes e terem sofrido diferentes tipos de pressão de seleção por inseticidas, não foi observada diferenciação cromossômica. Pela homosseqüencialidade cromossômica verificada entre as seis populações sugere-se que a espécie seja monomórfica e os fatores genéticos de resistência aos inseticidas estejam espalhados no genoma sem uma expressão aparente em nível cromossômico
Abstract: Chromosornic studies were carries out for six populations of Simulium (Chirostilbia) pertinax of BraziI. The analysis of the larval cerebral ganglia from the population found in Morungaba, SP showed that the species presents a karyotype with 2n=6 chromosomes, two pairs being metacentric and one pair submetacentric. Based on standard methodology for the Simuliidae family, the polytene chromosome maps were made using the larval salivary glands. Polytene chromosomes banding pattems presented high morphological homology. No important constrictions were recorded and assinaptic regions were rare. AIso, neither B chromosomes nor a sex differential segment were observed. Comparison of polytene chromosome band pattems with that considered standard for the subgenus Simulium showed a similarity of about 63% for many regions in all the six chromosome arms. Besides the population obtained from Morungaba (n=1O2) a study was also made of five S. pertinax populations collected respectively in the states of Paraná (Tibaji, n=13), Rio Grande do Sul (Nova Petrópolis, n=14), Rio de Janeiro (Muriqui, n=40) and São Paulo (Barra do Una, n=38; and llhabela, n=48). Comparisons for the polytene chromosomes within and among the six populations were carried out. Polytene chromosomes showed band pairing among homologous chromosomes and conspicuous centromeric regions. No difference was observed for any morphological chromosome characteristics such as centromeres, universal markers, nuclear organizer region (NOR) and banding pattem within and among populations, except by one individual expression of polymorphism, a secondary NOR. No chromosomal differentiation associated to insecticide resistance was observed a1though four of the populations presented different bioecological features and suffered different selection pressures by insecticides. Due to the chromosomal homosequentiality found among the six populations it was suggested that S. pertinax is a monomorphic species and that the genetic factors for organophosphorous resistance are spread in the genome with no visually detectable morphologic expressions at the chromosome level
Mestrado
Biologia Celular
Mestre em Ciências Biológicas

The structure of the mouthparts and distribution of cephalic sense organs of larval simuliids was investigated using the scanning electron microscope and methylene blue staining. The effect of water velocity, temperature and quality on larval feeding behaviour was studied in an artificial stream. Short, controlled, pulses of physical and chemical stimulants were injected into the water to observe their effect on larval feeding behaviour. Too rapid for the unaided eye, movements were described frame by frame from video recordings. Food is filtered from the water by the open cephalic fans. In alternation the fans are rapidly closed , swept by the mandible to remove food particles and opened again. The frequency of this endogenous behaviour pattern was modified by environmental factors that appeared to act mainly on the interval between fan beats. The interval between fan beats was found to be inversely related to water temperature and velocity and was also affected by water borne stimulants, being significantly shorter in unfiltered natural water than particle-free distilled water. Consequently fan cleaning frequency rose as water velocity and temperature were increased and when natural food was available. Larvae responded to pulses of a wide variety of chemical compounds with bursts of mandible and maxilla movements. Fan cleaning was inhibited when these mouthpart movements occurred but filtering continued. Short pulses of inert particles at a relatively high concentration caused a similar response but when a series of pulses was delivered bursts of mouthpart movements lengthened and the fans were often closed for longer than normal, inhibiting filtering. It is suggested that overstimulation of peripheral sense organs, responding to the physical and chemical qualities of food particles, initiates the inhibition of filtering. The temporary inhibition of feeding may regulate the rate of ingestion. A simple model of larval behaviour is proposed, recognising "food gathering" (filtering) and "food ingestion" (mouthpart movements) as its main components.

Orientador: Mohamed E. M. Habib
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: No presente trabalho foram investigados vários aspectos da patologia e epizotiologia de dois agentes biológicos, o microsporídeo Polydispyrenia simulii (Microspora; Duboscquiidae) e o nematódeo Gastromermis viridis cf (Nematoda; Mermithidae), que ocorrem naturalmente no borrachudo Simulium pertinax (Dip.; Simuliidae) na região estudada. Esta espécie de borrachudo apresenta elevada antropofilia, sendo alvo de práticas de controle no sul e sudeste do Brasil. O objetivo principal é a obtenção de dados para a correta avaliação do potencial destes organismos como agentes de controle biológico natural dessa espécie de borrachudo. Quanto aos estudos sobre a microsporidiose em S. pertinax foram feitas investigações histológicas em hospedeiros sadios e doentes, nos diferentes estágios de seu desenvolvimento (larva, pupa e adulto). Verificou-se que em larvas e pupas de S pertinax doentes, o tecido adiposo visceral é o sítio principal de replicação e desenvolvimento do protozoário, havendo também o comprometimento do tecido muscular e do epitélio intestinal no hospedeiro no estágio de larva. No estágio de pupa verificou-se que por processos histolíticos tem-se a debelação da doença e consequente ausência de esporos na fase adulta de S. pertinax. Apesar de não se detectar a presença de esporos nos ovários de fêmeas tanto coletadas no campo como obtidas no laboratório, verificou-se que como consequência da infecção larval, os indivíduos adultos, inclusive machos, apresentam algum comprometimento das gônadas. As fêmeas apresentam uma redução média de 31,2% na fecundidade enquanto que nos machos há uma sensível redução da motilidade dos espermatozóides. Além disso, constatou-se que a manutenção da microsporidiose no campo deve-se muito provavelmente a mecanismos de transmissão horizontal visto que a transmissão vertical não foi confirmada pelas investigações. Quanto aos estudos sobre G. viridis cf em S. pertinax, temos que sua prevalência anual em populações larvais do hospedeiro é baixa, variando de 0,8% a 14,3%. Sua ocorrência parece estar relacionada à vazão do riacho e consequente velocidade de corrente d'água. As investigações histopatológicas revelaram que o tecido adiposo visceral das larvas hospedeiras é o principal alvo da parasitemia, havendo também o comprometimento do tecido muscular e glândulas salivares. Verificou-se ainda que a parasitemia por G. viridis cf. causa redução significativa da resposta comportamental das larvas parasitadas face a qualquer estímulo fisico-químico ou mecânico. Além disso, o retardo no desenvolvimento do hospedeiro larval também foi verificado. Esse fenômeno é conhecido como metatetelia. Os resultados obtidos indicam que o microsporídeo P. simulii tem um significativo papel no controle natural das populações de S. pertinax, uma vez que reduz em quase um terço a fecundidade das fêmeas e promove um menor período de motilidade dos espermatozóides dos machos. Por outro lado, G. viridis cf. apesar de exaurir as reservas da larva hospedeira não apresenta elevada prevalência indicando uma pequena influência na regulação das populações hospedeiras. Acreditamos que alguns estudos ainda são necessários para a correta avaliação do potencial de G. viridis cf. como agente de controle biológico natural de borrachudos. O uso de ambos os agentes, P. simulii e G. viridis cf., nos parece promissor como ferramentas auxiliares para o Manejo Integrado destes incômodos dípteros
Abstract: The aim of the present work is to evaluate the potentiality of Polyd;spyren;a s;mulii (Microspora; Duboscquiidae) and Gastromerm;s v;r;d;s cf (Nematoda; Mermithidae) as two agents for biological control of the blackfly S;mulium pertinax (Diptera; Simuliidae). Pathological and epizootiological aspects of both agents were investigated. Histopathological studies revealed that the visceral fat body of S. pertinax larvae and pupae showed to be the main site of infection for P. s;mulii. The microsporidiosis also atIected the muscular tissue and midgut epithelium of larvae. It was detected that during host pupal development the spores of P. s;mulii were lised, causing the adults to became free of infection. Although no infection was detected in adults originated ITom heavly infected larvae, the number of ovarian folicules of females, as well as the mobility of spermatozoids in males were reduced. It was also detected that vertical transmission does not work on the microsporidiosis maintenance in host populations of S. pertinax. The results also indicated that P. s;mulii has a high influence as a natural control agent of S. pertinax populations. Epizootiological studies reveal that the annual prevalence of the nematode G. v;r;d;s cf in S. pertinax larvae population is low, ranging from 0,8% to 14,3%. Histopathological investigations in infected larvae showed that the visceral fat body was the principal target site of mermithid infection. The muscular tissue and the salivary glands were also atIected. Infected larvae of S. pertinax showed a reduced behavioural response to physical stimulii. Parasitized individuais showed a slower development, known as metatetely. The low prevalence rate of G. v;r;d;s cf in S. pertinax larval populations indicates that its etIects on the blackfly natural control are very small. More studies are necessary for the correct evaluation of G. v;r;d;s cf as biological control agent of S. pertinax. However, both agents may be helpful weapons in Integrated Management Programmes of this medically important insect
Doutorado
Doutor em Ciências Biológicas

Three major experiments on the anticoagulant components of the saliva of some black fly species were conducted. These included investigations on anticoagulant activities against factor Xa and thrombin in the salivary gland extracts (SGE) of Simulium argus Williston, S. vittatum Zettersted, S. metallicum Bellardi, and S. ochraceum Walker using in vitro, chromogenic substrate assays, biochemical and molecular characterization of the anti-thrombin from the saliva of S. vittatum and determination of the target enzyme in the vertebrate coagulation cascade of a novel anticoagulant from the saliva of S. vittatum. The study on anticoagulant activities in the four simuliid species revealed factor Xa inhibition to be common in all four species while thrombin inhibition was detected only in S. argus and S. vittatum. Both bovine and human α-thrombins were inhibited with the highest activity occurring with S. argus SGE. Factor Xa inhibition was highest in S. ochraceum which is an anthropophilic species and vector of Onchocerca volvulus, and lowest in S. vittatum, a primiparous autogenous species that is also zoophilic. Total soluble SGE protein also varied among the four species with the highest concentration measured in S. ochraceum and the lowest in S. vittatum. In the second experiment, the anti-thrombin component of the saliva of S. vittatum was purified using a two-step reverse phase (RP) high performance liquid chromatography (HPLC) involving a C-8 macrosphere column. The molecular weight of the HPLC purified inhibitor was determined by laser desorption ionization mass spectrometry (LDI-MS) and was found to be 11,333 daltons. Studies on the effect of the molecule on other serine proteinases such as α-chymotrypsin, human neutrophil elastase, and human neutrophil cathepsin G showed that they are inhibited by the salivary anticoagulant. The N-terminal sequence for the first 35 amino acids was determined. The molecule has been named Simulidin. In the third experiment, a novel anticoagulant from the saliva of S. vittatum, with activities on factor V, was demonstrated using the activated partial thromboplastin time (APTT) in HPLC partially purified salivary lysate. Factor Xa and thrombin were unaffected by the inhibitor.

O objetivo desta Tese é realizar o levantamento taxonômico e avaliar a dinâmica populacional de Simuliidae em localidades sob influência do Aproveitamento Hidrelétrico de Peixe Angical, TO. Os simulídeos possuem abrangente distribuição geográfica, e os estágios imaturos utilizam ambientes lóticos como sítios de criação. Algumas espécies podem atuar como vetores de vírus, protozoários e helmintos, o que confere ao grupo importância médica e veterinária. O hábito hematofágico das fêmeas de simulídeos pode acarretar sérios prejuízos ao turismo; ocasiona baixa no rendimento escolar; e na agropecuária dificulta a execução do trabalho o que reduz a produtividade. Durante a construção de grandes empreendimentos ocorre em pouco tempo à introdução de contingente populacional com drástica transformação do meio. A intervenção do homem sobre os ecossistemas e o crescimento desordenado pode provocar desequilíbrio ecológico que propicia a proliferação de espécimes vetores com consequentes problemas médico sanitários. A maior parte dos trabalhos realizados com insetos vetores em áreas sob influência da construção de hidrelétricas se refere aos culicídeos. O estudo dos aspectos taxonômicos permitirá o levantamento da biodiversidade e o diferencial deste projeto está no estabelecimento da sazonalidade e dinâmica das populações de imaturos e adultos de simulídeos. As amostras foram obtidas em áreas de influência direta e indireta da UHE Peixe no rio Tocantins, em 12 pontos diferentes de coleta, nos municípios deJaú do Tocantins, Peixe, Palmeirópolis, Paranã e São Salvador do Tocantins. Foram realizadas bimestralmente de 2004 a 2007, um total de 24 campanhas para coleta em criadouros pré-selecionados, que acompanharam todas as fases de construção início das obras, formação do lago, funcionamento da Usina. OS dados abióticos foram aferidos, e os imaturos removidos do substrato manualmente por 10 minutos e posteriormente preparados para eclosão dos adultos. Parte do material foi identificado no Laboratório de Simulídeos e Oncocercose do Instituto Oswaldo Cruz, onde foram verificados novos registros específicos para a ocorrência de Simuliidae em Tocantins, além do assinalamento de espécies antropofílicas e/ou vetores de Onchocerca volvulus. Nas áreas usadas para a formação do lago houve desaparecimento de criadouros. O desmatamento ocorrido aliado ao vigor dos simulídeos que conseguem realizar voos de longas distâncias na procura de alimento ou locais adequados a oviposição devem ter contribuído para a dispersão de espécimes. Há relatos sobre a da ocorrência de oncocercose na área estudada, um foco foi demarcado na divisa de Goiás com Tocantins, municípios Paranã e Minaçu investigado a partir de um caso autóctone de oncocercose. Este estudo é relevante uma vez que o Brasil possui potencial hidroenergético e prevê a construção de inúmeras hidrelétricas nos próximos anos. É importante estudas as áreas impactadas, conhecer a sua biodiversidade e os aspectos bioecológicos de Simuliidae no país.
This project aims to carry out the taxonomic survey and population dynamics of Simuliidae in locations under the use influence of hydroelectric power station at Peixe Angical (Tocantins). Immature black-flies use lotic environments as rearing sites. Some species are vectors of viruses, protozoa or helminths, which assigns them medical as well as veterinary importance. The blood feeding habits of females affect rural life causing financial damages to tourism, declining of school performance and reducing of agricultural productivity. During the construction of large enterprises the need of hiring extra personnel drastically affects the environment. Human intervention on ecosystems as well as disorderly population growth can cause ecological imbalance added to significant vector proliferation causing health as well as sanitary problems. Deforestation and exploitation in the river beds also affect population of black-flies dynamics influencing their geographical distribution. In specialized literature, most of the work carried out in hydroelectric construction areas is referred to culicidae. Studies that mention black-flies in impacted areas by hydroelectric power stations in Brazil are restricted to taxonomic survey and brief comments on the formation of lakes with consequent disappearance of breeding sites in lotic environments. This research work is part of a larger project that studies the black-flies and their local associated entomological fauna, which will allow us to carry out its biodiversity surveillance. The differential of this project is to establish the seasonality and population dynamics of immature as well as adult black-flies. Samples were obtained in areas of direct and indirect influence of Peixe Hydroelectric power station in 12 different collecting sites in the municipalities of Peixe, Paranã, Palmeirópolis, Jaú and São Salvador do Tocantins. Were conducted bimonthly from 2004 to 2007, a total of 24 campaigns, which accompanied building phases: start of groundwork, lake formation and operation of the plant. All abiotic data were registered and immature black-flies removed from the substrate for 10 minutes and prepared for the outbreaking of adults. Part of the material has been identified at the Simuliidae and Onchocerciasis laboratory at Oswaldo Cruz Institute, where new records of specific occurrence of Simuliidae in Tocantins have been registered, as well as anthropophilic species and / or vectors of Onchocerca volvulus. Mansonella ozzardi of vector species were not collected in the study area. It is expected that the prevalence is higher in the rainy months of the year. In areas where there was a lake formation there was loss of habitats. Black-flies can fly long distances in search of food or oviposition sites and that fact, coupled with deforestation may lead to the dispersal of species. There is a report on the occurrence of an autochthonous case of onchocerciasis in Paranã and Minaçu, municipality of Goiás and boarding area of the studied sites. This study is relevant to knowledge of biodiversity and bioecological aspects of Simuliidae in Brazil.

Le temephos ou abate etait le seul insecticide depuis 1974 par le programme de lutte contre l'onchocercose en afrique de l'ouest pour controler les stades aquatiques du vecteur simulium damnosum s. L. Une resistance a ce larvicide apparue en 1980 a necessite la recherche et l'utilisation de plusieurs autres larvicides appartenant a differentes familles chimiques. Les tests realises a court terme en gouttieres ont permis une classification de ces larvicides en fonction de leur niveau de toxicite globale sur la faune totale des insectes non-cibles. A long terme l'utilisation alternee des larvicides sur les cours d'eau ne facilite pas l'etude separee de l'impact de chacun d'eux. Neanmoins des typologies ont ete mises en evidence a partir des donnees sur la faune du dessus des rochers, permettant de distinguer les releves des periodes pre-traitements de ceux des periodes traitees au b. T. H-14, a l'abate ou autres larvicides. Des tentatives de prediction de l'impact a long terme a partir des resultats des tests a court terme ont ensuite ete discutees

Le protocole d'etude mis au point sur le modele de la resistance du moustique culex pipiens aux insecticides organophosphores dans le sud de la france, a permis de preciser la distribution des genes est-3**(a), codant pour une esterase de detoxication de grande activite, et ace**(r), codant pour une acetylcholinesterase moins sensible a l'inhibition par l'insecticide, ainsi que de caracteriser une nouvelle esterase de grande activite (est-4), egalement associee a la resistance. Ce protocole a ete egalement utilise pour etudier les mecanismes de resistance de c. Quinquefasciatus et de simulium damnosum s. L. De c ote d'ivoire. Une etude biochimique, immunologique et moleculaire a permis de demontrer que l'augmentation d'activite de l'esterase de detoxication de culex quinquefasciatus de californie (est-2**(a)) etait due a un mecanisme d'amplification genique. Un systheme complexe d'incompatibilites cytoplasmiques a ete mis en evidence chez c. Pipiens du sud de la france. L'importance de ce mecanisme de sterilite apparemment lie a la distance entre les gites mais non a leur nature, dans la structuration des populations est discutee en fonction des facteurs de variation observes

Simulium chutteri is considered a major pest in South Africa and it has been estimated that it can potentially cause stock losses amounting to more than R88 million per annum. Although a larval control programme has been launched to control the pest, major outbreaks still occur, since major fitness traits such as longevity are ignored in the planning of control actions. To improve the control programme, the aim of this study was to study the longevity of S. chutteri females under various conditions, and also to relate longevity to factors such as size, mass and metabolic reserves as these traits show variation that can be linked to changes in developmental temperature. It was conclusively demonstrated in this study that the body size and mass of S. chutteri increases with a decrease in temperature and therefore both seasonal and geographical variations occur. A consequence of larger body size is that these individuals carry proportionally more lipid reserves than smaller ones, although these relationships were not found for glycogen. It was shown that major seasonal variation occurred in the survival of S. chutteri, although these could not be attributed solely to variations in size, mass and metabolic reserves. For example, despite the large body size and mass and metabolic reserves of the winter population, it showed comparatively lower survival than all the other populations. It is argued that this is due to the interaction between fecundity and other fitness traits such as desiccation and starvation resistance. Adaptive explanations are, however, also proposed. These results are used to explain the seasonal variation found in the annoyance levels of S. chutteri along the lower Orange River. Moreover, recommendations are given for the improvement of the current blackfly control programme. These include the need to control the summer population (when certain criteria are met) and showing the importance of effectively controlling the winter population.
Dissertation (MSc (Entomology))--University of Pretoria, 2006.
Zoology and Entomology
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