Search

The mosquito Aedes aegypti is the primary vector of dengue and is common throughout tropical and subtropical regions. Its distribution is modulated by environmental factors, such as temperature. This study aimed to evaluate the influence of temperature on the life cycle and expansion of Ae. aegypti populations in the cities of Campina Grande, João Pessoa, and Patos. Samples of Ae. aegypti were collected in the three cities and raised in the laboratory. We assessed the life cycles of the three Ae. aegypti populations under six constant temperatures (16, 22, 28, 33, 36, and 39°C), selected on the basis of historical temperature tendencies of each city. We also used existing climate data to calculate projected temperature increases for all three areas. Our results suggest that Campina Grande, João Pessoa, and Patos will experience, respectively, maximum temperature increases of 0.030°C/year, 0.069°C/year, and 0.061°C/year, and minimum temperature increases of 0.019°C/year, -0.047°C/year, and -0.086°C/year. These projected increases will result in temperatures favorable to the Ae. aegypti life cycle, causing rapid population growth. Therefore, Ae. aegypti populations are likely to expand in the mesoregions represented by these cities.

OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Paraíba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos. OBJETIVO Avaliar a resistência de Aedes aegypti ao temefós Fersol 1G (temefós 1% p/p) quanto à desvantagem adaptativa ao inseto, na ausência de pressão de seleção. MÉTODOS Foi aplicada a dose diagnóstica de 0,28 mg i.a/L e concentrações entre 0,28 mg i.a/L e 1,4 mg i.a/L. Foram avaliadas amostras do vetor coletadas no município de Campina Grande entre 2007 e 2008, no estado da Paraíba. Para avaliar a competição na ausência de pressão de seleção, foram constituídos grupos de insetos com frequências iniciais de 20,0%, 40,0%, 60,0% e 80,0% de insetos resistentes, submetendo-os a dose diagnóstica por dois meses. Os ciclos de vida das populações suscetível e resistentes foram comparados avaliando-se as fases de desenvolvimento aquática e adulta, construindo-se tabelas de vida de fertilidade. RESULTADOS Não foram verificadas mortalidades nas populações de Ae. aegypti quando submetidas à dose diagnóstica de 0,28 mg i.a./L. A diminuição da mortalidade nas populações com 20,0%, 40,0%, 60,0% e 80,0% de indivíduos resistentes indica que a resistência ao temefós é instável na ausência de pressão de seleção. A comparação do ciclo de vida mostrou diferenças na duração da fase e viabilidade larval, mas não quanto ao desenvolvimento embrionário, razão sexual, longevidade dos adultos e número de ovos/fêmea. CONCLUSÕES Pelos parâmetros da tabela de vida de fertilidade constatou-se que algumas populações apresentaram desvantagens reprodutivas em relação à população suscetível na ausência de pressão de seleção, havendo custo adaptativo resultante da resistência ao temefós.

Introduction Aedes aegypti is responsible for the transmission of the dengue and yellow fever viruses. This study evaluated the effects of extracts from Cnidosculos phyllacanthus, Ricinus communis, and Coutarea hexandra on the developmental periods of A.aegypti larvae and pupae. Crude extracts of C. phyllacanthus and C. hexandra and oil from R. communis and C. phyllacanthus were used. Methods Bioassays of the larvicidal and pupicidal effects of these products at different concentrations and times of exposure were evaluated. The lethal and sublethal effects were determined using different concentrations in larvicidal tests. Mortality data were evaluated by Probit analysis to determine the LC50 and LC90 values. Results The vegetable oils from C. phyllacanthus and R. communis demonstrated greater efficiency for larval control with an LC50=0.28µl/mL and an LC90=1.48µl/mL and LC50=0.029µl/mL and a LC90=0.26µl/mL, respectively. In pupal tests toxic effects for all insects were verified after exposure to the products at significant LC50 and LC90 values for 24 and 48h. The effects of sublethal concentrations of C. phyllacanthus (oil) were more effective on the insects. Conclusions The vegetables oils from C. phyllacanthus and R. communis demonstrated greater potential from the control of different developmental periods in the life cycle of this insect.

O presente trabalho teve como objetivo comparar os ciclos de vida entre amostras de populações de Aedes aegypti (Linnaeus, 1762) coletadas em dez municípios localizados no semiárido paraibano. Os ciclos de vida foram estudados a uma temperatura de 26 ± 2ºC, umidade relativa de 60 ± 10% e fotofase de 12 horas. Diariamente foram avaliados os períodos de desenvolvimentos e as viabilidades das fases de ovo, larva e pupa, bem como a razão sexual, longevidade, tamanho e fecundidade dos adultos. Foi realizada uma análise de agrupamento, utilizando-se uma matriz de distância euclidiana através do método da média não-ponderada. As durações e viabilidades para as fases de ovo, larva e pupa apresentaram respectivamente, uma variação média de 3,7 a 4,7 dias e 82,8% a 97,7%, 9,1 a 10,8 dias e 91,2% a 99,2% e de 2,1 a 2,5 dias e 93,5% a 98,4%. O comprimento alar foi de 5,13 a 5,34 mm para as fêmeas e de 4,18 a 4,25 mm para os machos. A menor fecundidade (153,6 ovos/fêmea) ocorreu na população de A. aegypti oriunda de Pedra Lavrada, enquanto que a maior fecundidade (310,6 ovos/fêmea) foi constatada para A. aegypti de Campina Grande. A análise de agrupamento com base na similaridade dos dados biológicos revelou a formação de dois grandes grupos distintos, onde as populações de A. aegypti de Serra Branca e Cuité apresentam maior similaridade entre si. As diferenças de ciclos biológicos verificadas entre as populações de A. aegypti demonstra a capacidade dessa espécie de sofrer variações na sua biologia e se adaptar às diferentes condições ambientais, favorecendo a permanência deste inseto nessas áreas com aumento do risco de transmissão do vírus da dengue. The present work aims at comparing the life cycle between samples from different populations of Aedes aegypti (Linnaeus, 1762) collected in ten municipalities in the semi-arid region of state of Paraíba, Brazil. The life cycles were studied under 26 ± 2ºC, a relative humidity of 60 ± 10% and a 12 h photophase. The development period, egg viability, and larval and pupal survival, were evaluated daily, as well as the sex ratio, longevity, size, and fecundity of adults. We performed a cluster analysis, using a Euclidean distance matrix by the method of unweighted mean. The duration and viability for the egg, larval and pupal stages had, respectively, an average change of 3.7 to 4.7 days and 82.8% to 97.7%, from 9.1 to 10.8 days and 91.2% to 99.2%, and 2.1 to 2.5 days and 93.5% to 98.4%. The wing length ranged from 5.13 to 5.34 mm for females and from 4.18 to 4.25 mm for males. The population of A. aegypti originated from Pedra Lavrada registered the lowest fecundity (153.6 eggs/female), while the highest fecundity (310.6 eggs/female) was observed in Campina Grande. Cluster analysis based on the similarity of biological data revealed the formation of two major distinct groups, where populations of A. aegypti from Serra Branca and Cuité show greater similarity to each other. Differences in biological cycles were observed among populations of A. aegypti, demonstrating the ability of this species to vary in its biology and adapt to different environmental conditions. This may increase the number of A. aegypti that stay in these areas, thus increasing the risk of the dengue virus.

INTRODUCTION: The need for studies that describe the resistance patterns in populations of Aedes aegypti (Linnaeus) in function of their region of origin justified this research, which aimed to characterize the resistance to temephos and to obtain information on esterase activity in populations of Aedes aegypti collected in municipalities of the State of Paraíba. METHODS: Resistance to temephos was evaluated and characterized from the diagnostic dose of 0.352mg i.a./L and multiple concentrations that caused mortalities between 5% and 99%. Electrophoresis of isoenzymes was used to verify the patterns of esterase activity among populations of the vector. RESULTS: All populations of Aedes aegypti were resistant to temephos, presenting a resistance rate (RR) greater than 20. The greatest lethal dose 50% of the sample (CL50) was found for the municipality of Lagoa Seca, approximately forty-one times the value of CL50 for the Rockefeller population. The populations characterized as resistant showed two to six regions of α and β-esterase, called EST-1 to EST-6, while the susceptible population was only seen in one region of activity. CONCLUSIONS: Aedes aegypti is widely distributed and shows a high degree of resistance to temephos in all municipalities studied. In all cases, esterases are involved in the metabolism and, consequently, in the resistance to temephos.

Many species of bromeliads create an aquatic microcosm among their leaves. Besides their native aquatic fauna, these microcosms can be used by larvae of invasive mosquitoes like Aedes aegypti. We compared the mortality among A. aegypti larvae placed inside tanks of Aechmea fasciata bromeliads with larvae placed inside artificial microcosms and with microcosms with low pH (5.4), which simulate the acidic conditions found inside bromeliad tanks. A. aegypti larvae suffered a significantly higher mortality inside bromeliad tanks compared to larvae in control microcosms, but the mortality inside bromeliads did not differ statistically from that found in artificial microcosms simulating bromeliad acidic conditions. We concluded that bromeliad tanks tend to be a less suitable environment for the development of A. aegypti larvae than artificial containers due to the acidification generated by bromeliad physiology.

Objetivou-se comparar o ciclo de vida e estimar, com base em tabelas de vida de fertilidade, os padrões de fertilidade de populações de Aedes aegypti (L.). Os ciclos de vida foram estudados a 26 ± 2ºC, e fotofase de 12h, avaliando-se, diariamente, o período de desenvolvimento e a viabilidade das fases de ovo, larva e pupa, e a longevidade e fecundidade dos adultos e elaborando-se tabelas de vida de fertilidade. As durações das fases de ovo, larva e pupa, variaram de 3,9 a 4,5 dias, 6,4 a 8,3 dias e de 2,0 a 2,5 dias, respectivamente. Os parâmetros de tabela de vida para A. aegypti de Brejo dos Santos, Boqueirão, Itaporanga e Remígio foram, respectivamente: Ro = 104,03, 84,58, 113,37 e 91,18; rm = 0,92, 0,78, 0,89 e 0,88; e lambda = 2,50, 2,18, 2,43 e 2,41. As populações de Brejo dos Santos e Itaporanga mostraram o maior potencial de crescimento em relação às demais populações. Os resultados mostram que há um padrão diferenciado de crescimento e potencial biótico para as populações de A. aegypti provenientes de diferentes municípios da Paraíba. The present work aims at comparing the life cycle and estimating, based on life tables, the patterns of fertility of populations of A. aegypti (L.). The life cycles were studied at the temperature of 26 ± 2ºC, and 12h photophase. The development period, egg viability and larval and pupal survival were evaluated daily as well as adult longevity and fecundity. Tables of fertility life were built. The durations of egg, larva and pupa stages varied from 3,9 to 4,5 days, from 6,4 to 8,3 days and from 2,0 to 2,5 days, respectively. The life table parameters for A. aegypti from Brejo dos Santos, Boqueirão, Itaporanga and Remígio, being, respectively, Ro = 104,03, 84,58, 113,37 and 91,18; rm = 0,92, 0,78, 0,89 and 0,88; and lambda = 2,50, 2,18, 2,43 and 2,41. The populations of Brejo dos Santos and Itaporanga had the biggest potential of growth in relation to the other populations. The results showed a differentiated pattern of growth and a biotical potential in the populations of A. aegypti originated from different municipal districts of the state of Paraíba.

Background The continued use of chemical insecticides in the context of the National Program of Dengue Control in Brazil has generated a high selective pressure on the natural populations of Aedes aegypti, leading to their resistance to these compounds in the field. Fitness costs have been described as adaptive consequences of resistance. This study evaluated the biological and reproductive performance of A. aegypti strains and a field population resistant to temephos, the main larvicide used for controlling mosquitoes. Methods Comparative tests were performed with a resistant field population from the municipality of Arcoverde, Pernambuco State, Brazil, with a high rate of temephos resistance (RR = 226.6) and three isogenetic laboratory strains from the same origin (Araripina municipality, Pernambuco): RecR (RR = 283.6); RecRNEx (RR = 250.5), a strain under a process of resistance reversion; and RecRev (RR = 2.32), a reversed susceptible strain used as an experimental control. Results Our study revealed that the absence of selective pressure imposed by exposure to temephos, for five consecutive generations, led to a discrete reduction of the resistance ratio and the response of the detoxifying enzymes. Most of the 19 biological parameters were impaired in the resistant strains and field population. The analysis of the fertility life table confirmed the presence of reproductive disadvantages for the resistant individuals. Similarly, the longevity, body size, and total energetic resources were also lower for the resistant females, except for the last two parameters in the field females (Arcoverde). In contrast, the sex ratio and embryonic viability suffered no interference in all strains or population evaluated, regardless of their status of resistance to temephos. Conclusions The reproductive potential and survival of the resistant individuals were compromised. The parameters most affected were the larval development time, fecundity, net reproduction rate, and the generational doubling time. These fitness costs in the natural population and laboratory strains investigated are likely associated with maintaining the metabolic mechanism of resistance to temephos. Our results show that despite these costs, the highly temephos resistant populations can compensate for these losses and successfully overcome the control actions that are based on the use of chemical insecticides.

Female Aedes aegypti lay their eggs on nearly any moist substrate. Methods with potential to repel oviposition may reduce infestation, thereby contributing to control of epidemics. We evaluated the influence of Cnidoscolus phyllacanthus and Ricinus communis plant extracts on the oviposition behavior of A. aegypti. Lethal concentrations were first determined in experiments with larvae after 24 h of exposure, after which LC50 and LC90 were used to test oviposition repellency. The experiment consisted of an oviposition preference test based multiple-choice and no-choice assays. The Oviposition Activity Indices (OAIs) from the multiple-choice test using both R. communis and C. phyllacanthus were negative, suggesting oviposition repellent and deterrent activity. The LC90 of both plant extracts deterred oviposition by this vector, as demonstrated by an OAI = value of -1. In the choice study, mean oviposition values were significantly different between R. communis and C. phyllacanthus. In the absence of choice, mosquitoes laid eggs independent of the substrate. In conclusion, our OAI values indicate that all substrates used repelled oviposition by A. aegypti. Fêmeas de Aedes aegypti põem seus ovos em qualquer lugar úmido e com acúmulo de água. Métodos alternativos com potencial de repelência à oviposição de insetos reduz a infestação contribuindo para controlar epidemias. Avaliou-se a inluência de extratos de Cnidoscolus phyllacanthus e Ricinus communis sobre o comportamento de oviposição de A. aegypti. A repelência a oviposição foi avaliada a partir das concentrações letais CL50 e CL90 obtidas no teste com larvas deste vetor após 24 horas de exposição. O teste de preferência para oviposição de A. aegypti foi baseado em duas situações: teste de múltipla escolha e teste sem chance de escolha. Os resultados do Índice de Atividade de Oviposição (IAO) para o teste de múltipla escolha, para ambos R. communis e C. phyllacanthus, foram negativos. A CL90 de R. communis e C. phyllacanthus apresentaram atividade repelente de oviposição, sendo confirmado pelo IAO = -1. Diferença significativa entre as médias dos tratamentos foi verificado no teste com escolha tanto para R. communis quanto para C. phyllacanthus. No teste sem chance de escolha, os mosquitos ovipositaram independente do tipo de substrato. A partir dos valores de IAO, todos os produtos apresentaram ação repelente à oviposição de A. aegypti.

Egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) can be found in several crops attacking Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) eggs. It is therefore necessary to demonstrate the capacity of these natural enemies in suppressing populations of the pest to allow them to be used in biological control programs against that species. This work had the objective of evaluating the impact of egg layer distribution in S. frugiperda egg masses on the parasitism capacity of Trichogramma atopovirilia Oatman & Platner, 1983. Masses containing one, two, and three layers were used as treatments, and 1.6 parasitoid per egg of the pest were released. Parasitism percentage differences were observed among the three types of masses under study, on average 66.24 ± 8.56%, 45.20 ± 6.20%, and 40.10± 3.46% for egg masses with one, two, and three layers, respectively, demonstrating the potential of use of the parasitoid for the control of fall armyworm.

In this study we analyzed the impact of physical barriers of Spodoptera frugiperda (J. E. Smith) egg-masses on the behavior of Trichogramma atopovirilia Oatman & Platner and Trichogramma pretiosum Riley. The duration of drumming, drilling, oviposition, period spent over the egg-mass, and interval between parasitized eggs were timed, and the number of parasitized eggs were recorded. The presence of scales on the egg-masses caused a significant increase in the time spent by both parasitoids on each process and a decrease in the residence time over the egg-mass and in the number of parasitized eggs, with an increase in the number of egg layers. There was a significant decrease in the number of parasitized eggs in relation to egg-masses with one layer and no scales. We observed that the physical barriers in fall armyworm egg-masses changed the behavior of T. atopovirilia and T. pretiosum, affecting their parasitization capacity. O trabalho teve por objetivo avaliar o impacto da barreira física presente nas posturas de Spodoptera frugiperda (J. E. Smith) sobre o comportamento de Trichogramma atopovirilia Oatman & Platner e Trichogramma pretiosum Riley. Foram avaliados: duração do período de reconhecimento externo do ovo, penetração do ovipositor, oviposição, tempo de permanência sobre a postura, deslocamento da fêmea entre ovos parasitados e número de ovos parasitados. A presença de escamas sobre as posturas aumentou significativamente o tempo gasto em cada etapa do comportamento para ambos os parasitóides e diminuiu o tempo de permanência da fêmea sobre a postura. O aumento no número de camadas de ovos sobre a postura diminuiu significativamente o número de ovos parasitados em relação a posturas com uma camada de ovos e sem escamas. Foi observado que as barreiras físicas sobre as posturas de S. frugiperda alteraram o comportamento de T. atopovirilia e T. pretiosum, afetando sua capacidade de parasitismo.

The oviposition behavior of Spodoptera frugiperda (J. E. Smith) and natural parasitism of this pest by Trichogramma spp. at different phenological stages of corn were evaluated under field conditions. The distribution of S. frugiperda eggs varied according to the phenological stage of the corn. The preferred site for oviposition was the lower region of the plant and the abaxial leaf surface during the early development stages of the crop (4-6 leaves), changing to the middle and upper regions of the plant and the adaxial leaf surface at subsequent stages (8-10 and 12-14 leaves). A larger number of egg masses, and, therefore, of eggs was collected at the 4-6 and 8-10 leaf stages compared to plants in the 12-14 leaf stages. Natural parasitism was low, with a maximum of 2.21% eggs parasitized, especially on the lower and middle parts of the plant. The distribution and degree of parasitism by Trichogramma spp. on different regions of the plant were independent of the developmental stage of the crop. Trichogramma pretiosum Riley was the most frequent parasitoid, found in 93.79% of the parasitized eggs, followed by Trichogramma atopovirilia Oltman & Platner, with 2.07%.

Egg viability and nymphal development of the predatory bug Supputius cincticeps (Stål, 1860) were evaluated during two generations in the Biological Control Laboratory of the Núcleo de Biotecnologia Aplicada à Agropecuária (Bioagro/UFV) in Viçosa (Minas Gerais, Brazil) at 24.72±1.10ºC and photophase of 12 hours. Three treatments were represented by S. cincticeps fed with Zophobas confusa Gebien, 1906, Tenebrio molitor Linnaeus, 1758 and Musca domestica Linnaeus, 1758 larvae. Higher egg viability of this predator was found when the preys were Z. confusa and T. molitor, 74.46% and 80.91 %, than in M. domestica, 57.02%, but incubation period showed no differences between preys. Shorter nymphal development and higher nymphal viability were found with Z. confusa and T. molitor than with M. domestica. Higher weight increase was found for nymphs which originated males and females in the second generation specialy with the first two preys.

Egg viability and nymphal development of the predatory bug Supputius cincticeps (Stål, 1860) were evaluated during two generations in the Biological Control Laboratory of the Núcleo de Biotecnologia Aplicada à Agropecuária (Bioagro/UFV) in Viçosa (Minas Gerais, Brazil) at 24.72±1.10ºC and photophase of 12 hours. Three treatments were represented by S. cincticeps fed with Zophobas confusa Gebien, 1906, Tenebrio molitor Linnaeus, 1758 and Musca domestica Linnaeus, 1758 larvae. Higher egg viability of this predator was found when the preys were Z. confusa and T. molitor, 74.46% and 80.91 %, than in M. domestica, 57.02%, but incubation period showed no differences between preys. Shorter nymphal development and higher nymphal viability were found with Z. confusa and T. molitor than with M. domestica. Higher weight increase was found for nymphs which originated males and females in the second generation specialy with the first two preys.

Parasitóides de ovos do gênero Trichogramma podem se reproduzir por partenogênese arrenótoca ou telítoca. A telitoquia é determinada geneticamente ou induzida por endosimbiontes, como as bactérias do gênero Wolbachia. Em populações telítocas pode ocorrer ginandromorfismo, isto é, a presença de indivíduos com estruturas de machos e de fêmeas. No presente trabalho, foi observado ginandromorfismo em um exemplar de Trichogramma pretiosum Riley, que apresentou a genitália de fêmea e antenas características de macho. Esse fato nunca havia sido registrado em Trichogramma na América Latina. Egg parasitoids of genus Trichogramma can reproduce by arrhenotokous or thelytokous parthenogenesis. Thelytoky is genetically determined or induced by endosymbionts such as bacteria of the genus Wolbachia. In thelytokous Trichogramma populations, gynandromorphism - an individual having both male and female structures - can occur. Gynandromorphism was observed in one specimen of Trichogramma pretiosum Riley in which the individual presented female genitalia and male antennae, a fact never reported before in Trichogramma in Latin America.

The present research aimed at evaluating the influence of the water quality in the life cycle and attraction of Aedes aegypti (L.) females to oviposit using different sources of water (raw sewage, effluent of UASB reactor, effluent of polishing lagoon, effluent of anaerobic filter, rain water and de-chlorinated water). The immature development time and survivorship were evaluated on a daily basis in two distinct feeding systems (with and without food). The quality of the water was shown to affect the egg and larval stages, but not the pupal or the adult. In the absence of food, no development was observed in rain water and de-chlorinated water. Immature development was faster in water sources from raw sewage, although with the lowest survivorship (37.3%). Free-choice tests indicated that females preferred to lay most of their eggs on water collected from the effluent of a UASB reactor, achieving the highest oviposition activity index (OAI) of 0.57. In non-choice tests, females laid larger batches of eggs in water collected from anaerobic filters (204.8 eggs), with the lowest number of eggs being laid on de-chlorinated water (37.3 eggs). It can be concluded that A. aegypti does not demonstrate any particular preference to lay eggs on clean water. This has serious implications for developing strategies to manage populations of this important vector in urban areas as it was shown to lay eggs and successfully develop on several different sources of water.

A presente pesquisa teve por objetivo avaliar a influência da densidade larval sobre o ciclo de vida, tamanho e fecundidade de Aedes aegypti (L.). Os bioensaios foram conduzidos a 26 ± 2ºC e 12h de luz. Foram utilizadas cinco densidades larvais (200, 500, 750, 1000 e 1250 larvas/l) e dois sistemas de alimentação (um com alimentação fixa de 100 mg de ração e outro com quantidade de alimento proporcional ao número de larvas/bandeja). Avaliou-se diariamente, o tempo de desenvolvimento e sobrevivência de ovo e larva, a razão sexual, a longevidade, a fecundidade e o tamanho dos adultos. O ciclo de vida de A. aegypti foi significativamente afetado pela densidade quando ofertados 100 mg de ração por bandeja. O período de desenvolvimento larval aumentou de 8,3 para 37,9 dias, a fecundidade diminuiu de 105,7 para 41,8 ovos/fêmea assim como o comprimento alar de 4,6 mm para 3,6 mm, quando comparadas às densidades de 200 para 1250 larvas/l, respectivamente. Não foram detectadas diferenças significativas dessas variáveis quando foram ofertados 1,9 mg de ração por larva, exceto para o tamanho dos adultos. Fêmeas criadas a 1250 larvas/l foram maiores, com comprimento alar médio de 5,2 mm. We focused on the evaluation of the influence that the larval density have on the life cycle, size and fecundity of Aedes aegypti (L.). The bioassays were conducted at 26 ± 2ºC and at 12h light. Five larval densities (200, 500, 750, 1000 and 1250 larvae/l) and two feeding systems (one with a fixed amount of 100 mg of food, and other with an amount of food proportional to the number of larvae/tray) were tested. Egg and larval development time and survivorship, sex ratio, longevity, fecundity and the size of adults were evaluated on a daily basis. The life cycle of A. aegypti was significantly affected by the density when offered 100 mg of food per tray. The period of larval development increased from 8.3 to 37.9 days whereas female fecundity and wing length decreased from 105.7 to 41.8 eggs/female and from 4.6 mm to 3.6 mm, respectively, by changing from a density of 200 to 1250 larvae/l. Significant differences of these variables were not detected when offering 1.9 mg of food per larvae, except for the size of the adults. Females emerged from rearing densities of 1250 larvae/l grew larger, with an average wing length of 5.2 mm.

O trabalho teve por objetivo avaliar o efeito da qualidade da água no desenvolvimento de Aedes aegypti (Linnaeus, 1762). O ciclo de vida desse vetor foi estudado em águas de esgoto bruto, efluente de reator UASB, efluente de lagoa de polimento, efluente de filtro anaeróbio, água de chuva e água desclorada. Diariamente avaliaram-se o período de desenvolvimento e as viabilidades de ovo, larva, pupa, longevidade e a fecundidade dos adultos. A duração do período larval variou de 5,6 a 9,1 dias, sendo a sobrevivência baixa em águas de esgoto bruto, efluente de reator UASB, efluente de lagoa de polimento e efluente de filtro anaeróbio. Não foram observadas diferenças nas durações e viabilidades das fases de ovo e pupa, longevidade e fecundidade dos adultos. Constatou-se que, apesar da baixa viabilidade larval, é possível o desenvolvimento do A. aegypti em águas com elevados graus de poluição e que todos os tratamentos permitiram o desenvolvimento desse vetor. The present work aimed to estimate the effect of water quality in the development of Aedes aegypti (Linnaeus, 1762). The life cycle of this vector was studied in raw sewage water, effluent of UASB reactor, effluent of polishing lagoon, effluent of anaerobic filter, rainwater and de-chlorinated water. The development period, egg viability and larval and pupal survival were evaluated daily as well as the adult longevity and fecundity. The duration of larval period showed a variation of 5.6 to 9.1 days. Survival was considered low in raw sewage water, effluent of UASB reactor, effluent of polishing lagoon and effluent of anaerobic filter. No difference in terms of the duration and egg and pupal viability nor in the adult longevity and fecundity was detected. It was verified that despite a reduction in larval viability, A. aegypti could accomplish total development in waters with high pollution degree and that all the treatments were suitable to the development of this vector.

O trabalho teve por objetivo avaliar o efeito da temperatura sobre o ciclo de vida de Aedes aegypti (Linnaeus, 1762), determinar as exigências térmicas para o desenvolvimento e estimar o número de gerações anuais do inseto em campo. O ciclo de vida das populações de A. aegypti foi estudado nas temperaturas de 18, 22, 26, 28, 32 e 34 ± 2ºC e fotofase de 12 horas, determinando-se ainda os limites térmicos inferiores de desenvolvimento (Tb) e as constantes térmicas (K) e estimado o número de gerações anuais do inseto em laboratório e em campo. A temperatura favorável ao desenvolvimento de A. aegypti encontra-se entre 22ºC e 32ºC, e para a longevidade e fecundidade dos adultos entre 22ºC e 28ºC. As Tb, K de ovo a adulto, e o número de gerações anuais em campo foram de 11,33; 8,99 e 13,61ºC, 192,3; 213,2 e 116,5 graus-dias, e 23; 24,6 e 30,3 gerações para as populações de A. aegypti de Boqueirão (07º29'27''S, 36º08'09''W), Campina Grande (07º13'32''S, 35º54'15''W) e Remígio (06º58'1''S, 35º47'29''W), respectivamente. The present work aims at estimating, based on a biological study, the thermal exigencies to the development and the number of generations per year of Aedes aegypti (Linnaeus, 1762) (Diptera, Culicidae) in field. The life cycle of the A. aegypti populations has been studied at constant temperatures of 18, 22, 26, 28, 32 and 34 ± 2ºC, and 12 hours photophase. The low threshold temperature of development (Tb) and the thermal constant (K) have been determined. The number of generations per year in laboratory and field has also been estimated. The favourable temperature to the A. aegypti development its between 22ºC and 32ºC, and to the longevity and fecundity A. aegypti adult its between 22ºC and 28ºC. The egg to adult basal temperature, thermal constant and the number of generations in field were, in order, 11.33; 8.99 and 13.61 ºC, 192.3; 213.2 and 116.5 graus-days, and 23; 24.6 and 30.3 generations to A. aegypti populations from Boqueirão (07º29'27''S, 36º08'09''W), Campina Grande (07º13'32''S, 35º54'15''W) and Remígio (06º58'1''S, 35º47'29''W).

Parasitóides Trichogramma vêm sendo utilizados em todo o mundo como agentes de controle biológico devido à sua ampla distribuição geográfica, alta especialização e efi ciência no controle de muitas espécies-praga de lepidópteros. Para o entendimento dos resultados do parasitismo e superparasitismo de Trichogramma pretiosum Riley, estudaram-se os aspectos comportamentais e biológicos desse parasitóide sobre ovos de Sitotroga cerealella (Oliver). As variáveis investigadas foram: aceitação hospedeira e tempo de contato de T. pretiosum com o hospedeiro parasitado, porcentagem de emergência, porcentagem de indivíduos deformados, duração ovo-adulto, razão sexual, tamanho e longevidade de T. pretiosum e número de ovos de S. cerealella parasitados por fêmea descendente. Observou-se rejeição de parasitismo em ovos de S. cerealella previamente parasitados com 24, 72 e 120h de idade. A rejeição foi superior para ovos com 72h e 120h após o parasitismo em comparação com aqueles com 24h. Ovos previamente parasitados com 24h apresentaram maior tempo de contato por T. pretiosum comparados aos de 72h e 120h. Os descendentes oriundos de hospedeiros dos quais apenas um parasitóide se desenvolveu apresentaram-se todos maiores, sem deformidades e com maior capacidade de parasitismo, ao contrário dos indivíduos descendentes de hospedeiros em que dois parasitóides se desenvolveram. Entretanto, a longevidade de fêmeas descendentes não diferiu entre parasitóides oriundos de hospedeiros em que um ou dois parasitóides se desenvolveram. Pode-se concluir que T. pretiosum reconhece ovos previamente parasitados e que o superparasitismo resultou em menor sucesso reprodutivo do parasitóide. The parasitoid Trichogramma has been used worldwide as biological control agent due to its wide geographic distribution, high specialization and efficacy against many lepidopteran pests. Biological and behavioral traits of Trichogramma pretiosum Riley parasitizing Sitotroga cerealella (Oliver) eggs were studied aiming to a better understanding of the results from parasitism and superparasitism. The variables investigated were: host acceptance and contact time by T. pretiosum on parasitized host, percentage of parasitoid emergence, number of deformed individuals produced, egg-adult period, sex ratio, offspring female body size and longevity, and number of S. cerealella eggs parasitized/female. Parasitism rejection was observed on parasitized host eggs after 24, 72 and 120h of parasitism. The rejection was higher for eggs parasitized after 72h and 120h of parasitism as compared to the eggs after 24h of parasitism. T. pretiosum contact time on eggs after 24h of parasitism was greater than on 72 and 120h. The offspring produced from hosts from which a single parasitoid emerged were larger, exhibited no deformities and greater capacity of parasitism, different from those produced from eggs where two parasitoids emerged. Offspring longevity, however, was similar for females emerged from hosts from which one or two adults emerged. In conclusion, T. pretiosum was able to recognize previously parasitized eggs and the superparasitism reduced the parasitoid.reproductive success.

Relatos da resistência de Aedes aegypti (L.) ao temefós em vários estados brasileiros, justificou esta pesquisa que teve por objetivo verificar e caracterizar a resistência ao temefós de populações de A. aegypti da Paraíba. A resistência ao temefós foi avaliada e caracterizada a partir da dose diagnóstica de 0,012 mg/l, e de curvas de concentração-mortalidade. Os dados de mortalidade nas concentrações múltiplas foram submetidos à análise de Probit, sendo as razões de resistências calculadas a partir das CL50s das populações resistentes e da CL50 da população suscetível de laboratório. Todas as populações de A. aegypti mostraram-se resistentes ao temefós. A população do Sítio Piabas com RR = 4,0 apresentou baixa resistência, as populações de Campina Grande com RR = 6,0, Lagoa do Mato com RR = 9,3 e Capim de Cheiro com RR = 9,0 apresentaram moderada resistência, e Boqueirão com RR = 11,0, Brejo dos Santos com RR = 16,6 e Itaporanga com RR = 15,6 mostraram média resistência ao temefós. Os resultados confirmam a necessidade contínua de um programa de monitoramento e manejo da resistência de A. aegypti na Paraíba.

O trabalho teve por objetivo determinar as exigências térmicas para o desenvolvimento e estimar o número de gerações anuais de Aedes aegypti (L.) em campo. O ciclo biológico das populações de A. aegypti foi estudado nas temperaturas constantes de 18, 22, 26, 30 e 34ºC, e fotofase de 12h. Foram avaliados, diariamente, o período de desenvolvimento e a viabilidade da fase de ovo, sobrevivência de larva e pupa, longevidade e a fecundidade dos adultos, determinando-se, ainda, os limites térmicos inferiores de desenvolvimento (Tb) e as constantes térmicas (K). Em função dessas variáveis foram estimados os números de gerações anuais do inseto em laboratório e campo. A temperatura favorável ao desenvolvimento de A. aegypti encontra-se entre 21ºC e 29ºC, e para a longevidade e fecundidade os adultos entre 22ºC e 30ºC. As Tb s, Ks de ovo a adulto, e o número de gerações anuais em campo foram de 9,5, 8,5, 3,4, 7,1, 13,5ºC; 244,5, 273,9, 298,5, 280,9 e 161,8 graus-dias; e 21,9, 23,8, 24,2, 21,1 e 22,1 gerações para as populações de A. aegypti das regiões de Boqueirão, Brejo dos Santos, Campina Grande, Itaporanga e Remígio, respectivamente. The present work aimed at estimating the thermal requirements for the development and the number of generations per year of Aedes aegypti (L.) under natural conditions. The life cycle of A. aegypti populations was studied at constant temperatures of 18, 22, 26, 30 and 34ºC, and 12h photophase. The development period, egg viability and larval and pupal survival were evaluated daily as well as adult longevity and fecundity. The low threshold temperature of development (Tb) and the thermal constant (K) were determined. The number of generations per year in laboratory and field were also estimated. The favorable temperature to A. aegypti development is between 21ºC and 29ºC, and to longevity and fecundity is between 22ºC and 30ºC. The egg to adult basal temperature, thermal constant and the number of generations in field were, in order, 9.5, 8.5, 3.4, 7.1, 13.5ºC; 244.5, 273.9, 298.5, 280.9 and 161.8 degree-days; and 21.9, 23.8, 24.2, 21.1 and 22.1 generations in populations from Boqueirão, Brejo dos Santos, Campina Grande, Itaporanga and Remígio.

Trichogramma pretiosum Riley, 1879 is among the most widely used natural enemies to the control of pests in Brazil, thus its preservation on the agroecossystems through selectivity pesticids is fundamental. The selectivity of lambda-cyhalothrin, in two formulations, 50 CS and 250 CS, to T. pretiosum was evaluated the maternal generation and F 1 offspring. Eggs of Anagasta kuehniella (Zeller), were given immediately (1 hours), 24 and 48 hours after immersion in the chemical solutions, and eggs treated 0-24, 72-96 and 168-192 hours after parasitism. Lambda-cyhalothrin on the formulation 50 CS and 250 CS, was harmful to T. pretiosum when applied before the contact of the females with the host eggs. The formulation 250 CS was more harmful than the formulation 50 CS, affecting the parasitism capacity, longevity of the females, and survival of the F 1 offspring, when applied before and after parasitism. The reduction of the parasitism capacity on eggs of A. kuehniella before immersion in the chemical solutions was 27.39% and 53.12% to the formulation 50 CSA and 250 CS, respectively.

Comparou-se a capacidade de paratisimo e o desenvolvimento de Trichogramma atopovirilia Oatman & Platner e T. pretiosum Riley visando à seleção da espécie mais adequada para o controle de Spodoptera frugiperda (J. E. Smith). Os experimentos foram conduzidos em laboratório à temperatura de 25±2ºC, U.R. de 70±0% e fotoperíodo de 14L:10E. Tanto T. atopovirilia como T. pretiosum desenvolveram-se bem e mostraram-se adaptados a ovos de S. frugiperda, mesmo após serem criados por várias gerações em ovos de Anagasta kuehniella Zeller. Entretanto, fêmeas de T. atopovirilia foram mais agressivas e de maior especificidade à praga, já que apresentaram maior capacidade de parasitismo em posturas com diferentes barreiras físicas e maior aceitação pelo hospedeiro natural, em relação à A. kuehniella. Por este maior parasitismo e especificidade de T. atopovirilia aos ovos da praga, deve-se dar preferência à utilização desta espécie para controle de S. frugiperda. The parasitism capacity and development of Trichogramma atopovirilia Oatman & Platner and Trichogramma pretiosum Riley were studied in order to select the most suitable species to control Spodoptera frugiperda (J. E. Smith). The experiments were conducted under laboratory conditions at 25±2ºC, 70±10% RH and 14L:10D photoperiod. Both T. atopovirilia and T. pretiosum showed good development and adaptation to S. frugiperda eggs even after being reared for several generations in eggs of Anagasta kuehniella Zeller. However, T. atopovirilia females were more aggressive and showed higher specificity to the pest, with a higher parasitism capacity in eggs laid with different physical barriers and were more accepted by the natural host in comparison with A. kuehniella. Because of the higher parasitism rate and specificity of T. atopovirilia to the pest's egg this species should be given preference to control S. frugiperda.

The aim of this paper was to evaluate the biological characteristics and the capacity of 20 strains of Trichogramma pretiosum R. (Hymenoptera: Trichogrammatidae) to accept and develop through the eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). The strains Lsg 1 , Lsg 11 and Lsg 18 were more effective in parasitizing and developing through the eggs of S. frugiperda . The strains Lsg 11 and Lsg 18 presented a great aggressiveness and preference for the natural host even after having been developed for several generations in alternative host, Anagasta kuehniella Zeller.