<b>Structure of the thesis</b> The present work has been organized in two main parts: in the first one, the focus will be on the scientific and theoretical aspects of the evaporation process in presence of an inert gas flow while in the second all the technical aspects and more practical tests related to the real implementation of the micro-gravity experiment CIMEX-1 will be detailed. In any cases, the discussion will always start from the phenomenology observed considering that ” Nature is far more reach of any speculations.” <b>Part I: Evaporation in presence of inert gas</b> In chapter 1, a detailed presentation of the experimental setups for the on-ground tests is given together with the presentation of the qualitative and quantitative results obtained. Actually, the main parameters that regulate such kind of experiments are the mass flow rate of inert gas, the total pressure of the cell and the geometrical shape and dimensions of the evaporating regions. Consequently, the experiments aimed at covering the maximal possible combination of these three parameters with special attention to the variation of the inert gas flow and of the thickness of the evaporating liquid layer. More precisely, the liquid layer thickness was in the range 1.2 to 3.8 mm while the inert gas flow was set in the range 50 to 2500 ml/min. The pressure has been partially neglected as control parameter because its control was discovered not to be very reliable. The visualization system used in all the experiments consisted in a opportunely calibrated infrared camera. It allowed for having a quantitative analysis of the temperature distribution at the interface of the evaporating liquid. The infrared images also helped to follow the thermal history of the interface. In many cases, it has been possible to clearly observe the evolution of instability patterns at the interface that represent an original contribution to the understanding of such a kind of phenomena. The physical and mathematical modeling of the observed phenomenology will be the subject of the chapter 2. One of the peculiar issue of the problem under consideration is that the thermal gradient normal to the interface is not directly imposed like in the usual Marangoni-Bénard experience, but is a result of the cooling of the interface due to the evaporation. Moreover,the interface is subject to the shear stress of the inert gas flow and to the one due to the thermo-capillarity. Finally, the gas phase is to be considered as a mixture; this oblige to solve a diffusion problem in the gas phase. A physical model that takes into account the different aspects mentioned above is presented together with the governing equations and the appropriate boundary conditions. Numerical issues involved in solving the model are also analyzed. Numerical results obtained are finally discussed and compared when possible with experimental results. <b>Part II: Preparation of the CIMEX-1 experiment on-board the International Space Station.</b> In chapter 3, we will describe the main platforms used to perform low-gravity experiments. They will be classified according to the low-gravity level and to the low-gravity interval duration that could be ensured for experiments. According to these criteria, the list of the low-gravity platforms will be as follows: Drop Towers with 4 sec. of micro-gravity, Parabolic Flights that can assure not more than 25 sec., Sounding Rockets with a low-gravity time of the order of several minutes depending on the rockets, Foton Capsules that assure for many days of high quality - i.e. without perturbations - low-gravity level and , last but not least, the International Space Station where the low-gravity duration could be even of several weeks which is a sufficient time duration for the most part of the experiments. The chapter 4 will be entirely devoted to the ITEL experiment that is the precursor and the core of the CIMEX-1. After a brief overview of the experiment that has been performed twice on-board sounding rockets of the MASER class, the experimental setups used both on-ground and in micro-gravity will be detailed. The focus will be on the experimental results obtained on-ground during the preparatory tests and during the two sounding rocket flights with special attention to the first one. The analysis will be supported by the presentation of many results obtained in numerical simulations. The two parabolic flight campaigns performed to test one of the key sub-systems of the CIMEX-1 setup are the subject of the chapter 5. The separating-condensing unit is mandatory for performing the experiment on-board the International Space Station because the limitations on the crew intervention oblige to have a closed loop experiment. The goal of the two parabolic flights will be detailed together with the setup and the experimental scenario. The main results will be also shown and some considerations on the efficiency of the system will be presented. It is worthy to stress that the results obtained during these parabolic flights have been determinant at the European Space Agency level to fly the CIMEX-1 experiment on-board the International Space Station. Finally, in the section conclusions and perspectives the main results obtained will be summarized together with the new scenarios opened by the present work and some guidelines for further development in the experimental, theoretical and technical analysis.

The bedbugs Cimex lectularius and C. hemipterus (Hemiptera: Cimicidae) have been identified from a study area in northern Natal and KwaZulu. South Africa, between 26° 45' S and 28° 45' S, and 32° 00 ' E and 32° 52' E. Morphological behavioural data suggest that the pigeon bug, C. columbarius, which closely resembles C. lectularius, is not present in Zulu huts. Two characters are suggested to supplement Usinger's (1966) key for distinguishing the nymphal stages of C. lectularius, and a key is presented for the case of G. hemipterus. Distinguishing features between the nymphal stages of the two species are also given. The two species were found to be sympatric over most of the study area, with C. hemipterus the more plentiful species in the north and apparently still in the process of invading the study area. Evidence was found that C. hemipterus replaces C. lectularius in huts where initially both species were found, and this agrees with laboratory findings that interspecific mating tends to shorten the life span and reduce the egg production of female C. lectularius females. Interspecifically mated female C. lectularius can be recognised by an easily visible morphological change in the reproductive system (Walpole, 1988b) and this character was used to prove that interspecific mating takes place in the wild. The size and life-stage composition of bedbug infestations were investigated together with factors likely to affect their growth. Cimex hemipterus was found not to be at a disadvantage as regards rate of egg production despite low temperatures in the wild, which suggested that such interspecific differences apparent in the laboratory may be an artifact. The specific status of C. lectularius and C. hemipterus are discussed, with particular reference to their cross-mating in the wild and the production of a hybrid. The acceptability of the Recognition Concept of species (Paterson, 1985) is considered in detail. The susceptibilities of wild bedbugs of both species to DDT, dieldrin and fenitrothion were tested in comparison with a susceptible strain of C. lectularius. Field trials of bendiocarb, deltamethrin and fenitrothion were carried out involving monitoring by bioassay and insecticidal knockdown. Subsequent to successful bedbug control operations, reinfestation rates and rates of replastering of mud walls of huts (an indigenous method of attempted bedbug control inimicable to malaria control operations) are assessed. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1989.

Hematophagy, or blood-feeding behavior, has independently evolved multiple times in the class Insecta and results in the transmission of vector-borne parasites, bacteria and viruses causing 17% of all infectious diseases and over 700,000 human deaths annually. One of the major challenges in studying the discrete mechanisms involved in host-response to hematophagy or the host seeking behavior of hematophagous insects, is the vast amount of signaling processes and genes that are inextricably tied to these interactions. These experiments used the clustered regularly interspersed short palindromic repeat (CRISPR)/CRISPR-associated (Cas) and dsRNA knock-down technologies to examine mechanisms of immunological reactivity and host-seeking behavior. Using Illumina next-generation sequencing, 19,269 unique genes were found to be expressed in the salivary glands of C. lectularius. Of those genes, a total of 10,587 were differentially expressed. There were 6 genes definitively characterized as nitrophorin or nitrophorin-like, which were targeted for RNAi experiments. Silencing two nitrophorin genes, LOC106662976 and LOC106662977, which were the most highly expressed, did not result in any significant changes in feeding behavior or dermal reaction in the host. While RNAi-based knock-down experiments can gauge a proteins function, CRISPR/Cas-based knock-out experiments more definitively assess functionality. The second part of the study is thus focused on performing the first homology directed repair knock-in in Ae. albopictus using a plasmid, Cas9 protein and sgRNA targeting the key olfactory receptor gene, AealbOR4. An injection plasmid was constructed targeting AealbOR4 using standard molecular methods. Preliminary injections of the plasmid yielded no viable embryos. To determine if it is the plasmid or injection components that are lethal to developing Ae. albopictus embryos, further studies are required. Despite this, the development of this technique is a first step to be able to effectively interrogate gene function of an olfactory receptor and its role in host-seeking behavior. Taken together, these studies indicate that both RNAi and CRISPR/Cas-based gene editing technologies can effectively be utilized to answer some of the intricate questions related to insect-host interactions in the future.

Depuis les années 90, on constate une augmentation mondiale des nuisances par punaises de lits (Cimex lectularius). En 2008 en France, peu d'observations et de recherche sont recensés. Cette thèse a eu pour objectif de mettre en place un groupe de recherche multirégional (Nice, Marseille, Toulon, Montpellier, Bobigny, Créteil) via un Projet Hospitalier de Recherche Clinique (PHRC 09-API-01). Sur le plan entomologique nous avons décrit 81 cas d'infestations, et nous avons récolté sur le terrain 2891 punaises Nous avons mis en place un élevage pérenne en laboratoire de Cimex lectularius nourries sur membrane par sang humain. Des investigations microbiologiques on été mené a partir de 339 punaises collectés précédemment, l'ADN et l'ARN ont été extrait pour évaluer leur portage virologique et bactériologique. En virologie, avec les sondes virales : Flavivirus, Arenavirus, Hantavirus, Phlebovirus aucune positivité a été observée. En bactériologie, 32 punaises ont été positives pour un agent infectieux soit 9.4% des punaises, 29 punaises ont été positives pour Acinetobacter, 3 pour Wolbachia, 3 pour Ehrlichia et 2 pour Coxiella. La sensibilité aux insecticides a été testée lors d'une collecte de 192 appartements de St Ouen (93). Au total 564 punaises ont été recueillies. L'ADN extrait pour 124 spécimens étaient homozygote pour le gène de résistance aux pyréthrinoïdes L925I kdr-gène. Ce taux élevé indique que le phénomène résistance est déjà bien établi. La pertinence de l'utilisation des pyréthrinoïdes pour contrôler les punaises de lit en France doit être discutée. / Since 90's, bed bugs (Cimex lectularius) infestations are increasing all over the world. Upon 2008, in France, very rare informations and researches on bedbugs are investigated. The objectives of this thesis work were to organise and manage a research project (PHRC 09-API-01) with french research laboratories (Nice, Marseille, Toulon, Montpellier, Bobigny, Créteil). About entomological project, we describe 81 infestations and collected 2891 bed bugs. A bed bugs maintenance of laboratory colony has been established without any animals, only on an artificial membrane with human blood. About Infectious research, 339 bedbugs have been studies for their virological and bacteriological pathogens. In virology, with the molecular probes targeted for Flavivirus, Arenavirus, Hantavirus, Phlebovirus no postivity has been observed. In bacteriology, 32 bedbugs have been positive for a bacteria dispatched as follow: 29 bed bugs for Acinetobacter, 3 for Wolbachia, 3 for Ehrlichia and 2 for Coxiella. Resistance to insecticide has been evaluated for 192 apartments in Saint Ouen City (France-93). 534 bed bugs have been collected. A total of 564 bed bugs were collected in the infested units. Bioassays and DNA sequencing showed a high frequency of resistance to pyrethroids; all bed bugs tested (n= 124) had homozygous L925I kdr-like gene mutation. The high levels of pyrethroid resistance indicate that this phenomenon is already established and prompt the need to reevaluate the wide use of pyrethroids to control bed bugs in France. Genetic analysis of french bed bug populations are still ongoing. First steps for biomolecular markers validations are finish.

Os cimicídeos, conhecidos popularmente como percevejos-de-cama, são insetos hematófagos durante os estágios de ninfas e adulto. Algumas espécies apresentam marcante antropofilia e apesar de não transmitirem patógenos, podem causar algumas complicações a saúde humana, como alergias graves e anemia. O número de infestações nos últimos anos em muitos países tem aumentado significativamente e a relação com lugares de baixo IDH não é mais observada, inclusive na cidade de São Paulo. A precariedade nos estudos dificulta o conhecimento sobre as infestações. No presente estudo, teve-se o objetivo descrever infestações no estado de São Paulo e seus aspectos, e estudar a morfologia dos percevejos de cama encontrados, através de análise morfométrica. Foram coletadas e descritas cinco infestações, quatro na cidade de São Paulo e uma na cidade de Mirandópolis. Os resultados sugerem haver falta de conhecimento da população sobre esta praga urbana e comfirmam Cimex lectularius como principal espécie presente no estado de São Paulo, assim como sugere uma proximidade populacional das infestações dentro da cidade de São Paulo em relação a infestações de outras localidades. Porém os estudos devem ser estimulados no intuito de enriquecer o conhecimento sobre estes insetos, haja vista o grande fluxo de pessoas e a possibilidade de agravamento das infestações, uma vez que grandes eventos internacionais ocorrerão em capitais brasileiras. / The Cimicidae, commonly known as bedbugs are bloodsucking insects throughout all their life cycle. Some species show striking anthropophily and despite they dont transmit diseases they can cause some complications for human health, such as severe allergies and anemia. The number of infestations over the last few years in many countries has increased significantly compared to places with low HDI that is no longer observed, including São Paulo city. The lack of studies hinders knowledge about infestations. The present study aims to describe infestations in the state of São Paulo and its aspects, and to study the morphology of bedbugs found, through morphometric analysis. Five infestations in the city of São Paulo and one in the city of Mirandópolis were collected and described. The results suggest lack of knowledge of the population about this urban blight and confirm Cimex lectularius as the main species present in the state of São Paulo. Also suggests proximity of infestations within the city of São Paulo in relation to infestations of other localities. However, the studies should be encouraged in order to enrich the knowledge about these insects, considering the large flow of people and the possibility of aggravating the infestation, since large international events will occur in the largest Brazilian cities.

Os percevejos de cama são insetos pertencentes a ordem Hemiptera e a família Cimicidae, com metamorfose hemimetábola, possuem comportamento antropofílico e exercem a hematofagia nas fases de ninfa e adulto, o que desperta interesse em saúde pública. O reaparecimento desta praga tem levado diversas pessoas a buscarem nas empresas especializadas uma forma de exercer o controle. O presente estudo teve como objetivo identificar, no período de maio de 2013 a maio de 2015, as formas de controle e produtos utilizados, bem como o perfil das empresas especializadas no controle de vetores e pragas urbanas instaladas no Brasil. O estudo foi realizado por meio de uma enquete enviada a 2136 empresas brasileiras e questionário eletrônico enviado para as empresas. Foram encaminhadas 2136 cartas convites para participação. Como resultado foi obtido 158 enquetes respondidas e estas empresas foram então convidadas a responder um questionário com perguntas direcionadas ao controle de percevejos de cama. Apenas 13 questionários foram recebidos de empresas localizadas na região Sul, Sudeste, Centro-Oeste e Nordeste. A maioria das empresas que realiza o controle de percevejos de cama está na área de controle de pragas urbanas a mais de 21 anos e utiliza preferencialmente pesticidas para o controle dos insetos. Quase 50 por cento dos responsáveis técnicos dessas empresas não fizeram qualquer treinamento sobre controle de cimicídeos nos últimos dois anos e informações sobre o inseto e seu manejo não são passadas ao cliente. O baixo retorno dos questionários preenchidos nesta pesquisa pode ser devido ao pouco conhecimento que as empresas têm sobre o controle de percevejos de cama, o que pode tê-las inibido em fornecer informações. Desta maneira, informações técnicas e treinamentos sobre o controle de percevejos de cama se faz necessário, uma vez que o controle ainda está pautado na utilização de produtos químicos e que esta estratégia pode incorrer em riscos de intoxicação quando feita de maneira inadequada principalmente pela falta de capacitação dos responsáveis técnicos. / Bed bugs belong to the order Hemiptera and family Cimicidae with hemimetabolous metamorphosis; they show anthropophilic behavior and are hematophagous at nymph and adult stages, which causes interest in public health. The reappearance of this pest has led many people to seek for pest control companies to control it. This study aimed to identify, from May 2013 to May 2015, which are the control strategies and used products as well as the profile of the pest control companies in Brazil. The study was made through an electronic survey sent to 2136 Brazilian companies, One hundred and fifty eight companies answered the survey and were invited to fill in a questionnaire on bed bug control. Only 13 questionnaires were received from companies located in the South, Southeast, Midwest and Northeast regions of Brazil. Most companies that make bed bug control are in the area for more than 21 years and they use mainly pesticides to control the insects. Almost 50 per cent of the technical managers of these companies did not attend to any training on bed bug control in the last two years, and information on their management is not given to their clients. The few questionnaires received are probably due to the little knowledge that pest control companies have on bed bugs, which may have inhibited them to provide information. In this way, technical information and training on the bed bug control is necessary, since the control is still founded on the use of chemicals and that this strategy may incur intoxication risk when done improperly mainly by lack of training of technical experts.

Os percevejos de cama são insetos pertencentes a ordem Hemiptera e a família Cimicidae, com metamorfose hemimetábola, possuem comportamento antropofílico e exercem a hematofagia nas fases de ninfa e adulto, o que desperta interesse em saúde pública. O reaparecimento desta praga tem levado diversas pessoas a buscarem nas empresas especializadas uma forma de exercer o controle. O presente estudo teve como objetivo identificar, no período de maio de 2013 a maio de 2015, as formas de controle e produtos utilizados, bem como o perfil das empresas especializadas no controle de vetores e pragas urbanas instaladas no Brasil. O estudo foi realizado por meio de uma enquete enviada a 2136 empresas brasileiras e questionário eletrônico enviado para as empresas. Foram encaminhadas 2136 cartas convites para participação. Como resultado foi obtido 158 enquetes respondidas e estas empresas foram então convidadas a responder um questionário com perguntas direcionadas ao controle de percevejos de cama. Apenas 13 questionários foram recebidos de empresas localizadas na região Sul, Sudeste, Centro-Oeste e Nordeste. A maioria das empresas que realiza o controle de percevejos de cama está na área de controle de pragas urbanas a mais de 21 anos e utiliza preferencialmente pesticidas para o controle dos insetos. Quase 50 por cento dos responsáveis técnicos dessas empresas não fizeram qualquer treinamento sobre controle de cimicídeos nos últimos dois anos e informações sobre o inseto e seu manejo não são passadas ao cliente. O baixo retorno dos questionários preenchidos nesta pesquisa pode ser devido ao pouco conhecimento que as empresas têm sobre o controle de percevejos de cama, o que pode tê-las inibido em fornecer informações. Desta maneira, informações técnicas e treinamentos sobre o controle de percevejos de cama se faz necessário, uma vez que o controle ainda está pautado na utilização de produtos químicos e que esta estratégia pode incorrer em riscos de intoxicação quando feita de maneira inadequada principalmente pela falta de capacitação dos responsáveis técnicos. / Bed bugs belong to the order Hemiptera and family Cimicidae with hemimetabolous metamorphosis; they show anthropophilic behavior and are hematophagous at nymph and adult stages, which causes interest in public health. The reappearance of this pest has led many people to seek for pest control companies to control it. This study aimed to identify, from May 2013 to May 2015, which are the control strategies and used products as well as the profile of the pest control companies in Brazil. The study was made through an electronic survey sent to 2136 Brazilian companies, One hundred and fifty eight companies answered the survey and were invited to fill in a questionnaire on bed bug control. Only 13 questionnaires were received from companies located in the South, Southeast, Midwest and Northeast regions of Brazil. Most companies that make bed bug control are in the area for more than 21 years and they use mainly pesticides to control the insects. Almost 50 per cent of the technical managers of these companies did not attend to any training on bed bug control in the last two years, and information on their management is not given to their clients. The few questionnaires received are probably due to the little knowledge that pest control companies have on bed bugs, which may have inhibited them to provide information. In this way, technical information and training on the bed bug control is necessary, since the control is still founded on the use of chemicals and that this strategy may incur intoxication risk when done improperly mainly by lack of training of technical experts.

Os cimicídeos, conhecidos popularmente como percevejos-de-cama, são insetos hematófagos durante os estágios de ninfas e adulto. Algumas espécies apresentam marcante antropofilia e apesar de não transmitirem patógenos, podem causar algumas complicações a saúde humana, como alergias graves e anemia. O número de infestações nos últimos anos em muitos países tem aumentado significativamente e a relação com lugares de baixo IDH não é mais observada, inclusive na cidade de São Paulo. A precariedade nos estudos dificulta o conhecimento sobre as infestações. No presente estudo, teve-se o objetivo descrever infestações no estado de São Paulo e seus aspectos, e estudar a morfologia dos percevejos de cama encontrados, através de análise morfométrica. Foram coletadas e descritas cinco infestações, quatro na cidade de São Paulo e uma na cidade de Mirandópolis. Os resultados sugerem haver falta de conhecimento da população sobre esta praga urbana e comfirmam Cimex lectularius como principal espécie presente no estado de São Paulo, assim como sugere uma proximidade populacional das infestações dentro da cidade de São Paulo em relação a infestações de outras localidades. Porém os estudos devem ser estimulados no intuito de enriquecer o conhecimento sobre estes insetos, haja vista o grande fluxo de pessoas e a possibilidade de agravamento das infestações, uma vez que grandes eventos internacionais ocorrerão em capitais brasileiras. / The Cimicidae, commonly known as bedbugs are bloodsucking insects throughout all their life cycle. Some species show striking anthropophily and despite they dont transmit diseases they can cause some complications for human health, such as severe allergies and anemia. The number of infestations over the last few years in many countries has increased significantly compared to places with low HDI that is no longer observed, including São Paulo city. The lack of studies hinders knowledge about infestations. The present study aims to describe infestations in the state of São Paulo and its aspects, and to study the morphology of bedbugs found, through morphometric analysis. Five infestations in the city of São Paulo and one in the city of Mirandópolis were collected and described. The results suggest lack of knowledge of the population about this urban blight and confirm Cimex lectularius as the main species present in the state of São Paulo. Also suggests proximity of infestations within the city of São Paulo in relation to infestations of other localities. However, the studies should be encouraged in order to enrich the knowledge about these insects, considering the large flow of people and the possibility of aggravating the infestation, since large international events will occur in the largest Brazilian cities.

Populations of Cimex lectularius, the bed bug, have resurged around the world posing significant challenges for pest management professionals and causing physical, economic, and emotional strife. Pyrethroid resistance has been found in the vast majority of populations making pest management more difficult. The objectives of my dissertation research were to document the evolution of resistance to pyrethroid and neonicotinoid combination products (called combination products here) and to a neonicotinoid in the laboratory, to record potential fitness costs to resistance to the combination products, and to compare the efficacy of nine insecticides on six populations. In the laboratory, populations of bed bugs evolve resistance rapidly to a combination product and that resistance translates into cross resistance to another combination product. In a follow up experiment, resistance to a neonicotinoid occurred after three generations of selection. Cross resistance between neonicotinoid and pyrethroid resistance was also found, likely due to a common detoxification mechanism (cytochrome P450 mediated metabolism). Resistance was associated with life history costs in three populations that had been selected with a combination product. Therefore, in the absence of selection pressure, populations of bed bugs should revert towards increasing susceptibility. Two pyrethroid products and three combination products were effective at killing three populations of bed bugs but were relatively ineffective against three other populations. However, the combination product, Transport GHP®, the single action pyrrole product, Phantom SC®, and the single action desiccant, CimeXa®, killed 95 to 100% of all populations investigated over a 14-day exposure. Taken together, results reported in this dissertation suggest that insecticide resistance management may be a useful tool for extending the efficacy of insecticides for control of C. lectularius.

No description available.