Ao longo do processo evolutivo, parasitóides desenvolveram a habilidade de manipular inúmeros processos fisiológicos de seus hospedeiros. Entre os efeitos induzidos pelo parasitismo, incluem-se alterações no ambiente nutricional, sistema endócrino e imunológico do hospedeiro, além da manipulação da capacidade de síntese protéica de seus tecidos. O tecido adiposo é o principal órgão de síntese de proteínas em insetos e a manipulação de sua atividade é de fundamental importância para o sucesso do parasitismo. Este trabalho teve por objetivo avaliar a expressão gênica do tecido adiposo de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) parasitada por Cotesia flavipes (Cameron) (Hymenoptera: Braconidae), visando à obtenção de dados para o desenvolvimento de novas estratégias de controle da broca da cana-deaçúcar. Lagartas de D. saccharalis na pré-muda para o último ínstar foram separadas, sendo parte delas sujeita ao parasitismo por C. flavipes, enquanto outra foi mantida como controle. O tecido adiposo de hospedeiros sadios e parasitados foi coletado 1, 3, 5, 7 e 9 dias após o parasitismo e submetido a extração de RNA, síntese de cDNA e análise de expressão gênica diferencial via DD-PCR (Differential Display PCR). Fragmentos expressos diferencialmente entre os tratamentos foram selecionados, clonados e sequenciados. As sequências obtidas foram comparadas àquelas disponíveis em banco de dados. C. flavipes induziu alterações na expressão de um transcrito codificador de uma proteína de armazenamento logo no início do parasitismo. As proteínas de armazenamento, ou hexamerinas, apresentam grande importância no desenvolvimento de insetos, atuando como fonte de aminoácidos a serem utilizados pela pupa e adulto durante a metamorfose e reprodução. Dada a importância desta proteína, o cDNA responsável por sua codificação foi caracterizado via extensão das porções terminais 5 e 3. A sequência completa do cDNA apresentou 2.353 pb, e o polipeptídeo deduzido, 745 aminoácidos. O conteúdo de metionina e aminoácidos aromáticos, bem como a análise filogenética realizada, indicaram que a hexamerina identificada em D. saccharalis é uma proteína rica em metionina. A identificação e caracterização da hexamerina de D.saccharalis podem representar o primeiro passo para o desenvolvimento de novos métodos de controle da broca da cana-de-açúcar, baseados nas interações hospedeiro-parasitóide / During evolution, parasitoids evolved the ability to manipulate the physiology of their hosts. Among the common effects of the parasitism, hosts may show an alteration of their hemolymph composition (parasitoid nutritional environment), endocrine and immune systems, and protein synthesis activity of host tissues. The fat body is the main organ of protein synthesis of insects and the manipulation of its activity is key for parasitoid successful development. The goal of this study was to evaluate the effects of parasitization by Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) on the gene expression activity of the fat body of Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), to provide additional information on key regulatory pathways to control host metabolism as a step forward for the development of new control strategies based on parasitoid host regulation strategies. Fifth-instars of D. saccharalis at the head slippage stage were isolated and separated in two different groups. One group was individually parasitized by C. flavipes, and the other was kept as control. The fat bodies of parasitized and non-parasitized hosts were collected 1, 3, 5, 7 and 9 days after parasitism, subjected to RNA extraction, cDNA synthesis and differential gene expression analysis by DD-PCR (Differential Display PCR). Transcripts that were differentially expressed between treatments were selected, cloned and sequenced. The obtained sequences were compared to those available at the NCBi data bank. C. flavipes up-regulated the expression of a transcript enconding for a storage protein soon after parasitization. The storage proteins, or hexamerins, are essential for insect development, acting as a reservoir of aminoacids and nitrogen to be used by the pupa and adults during metamorphosis and reproduction. Due to the importance of these proteins, the cDNA encoding this protein was characterized by the amplification of 5 and 3 terminal ends. The complete cDNA has 2,353 bp and the deduced aminoacid sequence is 745 aa long. The methionine and aromatic aminoacids content, as well as phylogenetic analysis, indicated that the hexamerin identified in D. saccharalis is a methionine-rich protein. The identification and characterization of the hexamerin identified in D. saccharalis is the first step towards to the development of new control strategies based on host-parasitoid interactions.

Desde 2004 foram detectadas, nas áreas citrícolas paulistas, as bactérias responsáveis pela principal doença de citros no mundo, o huanglongbing ou greening. A ampla distribuição no Brasil do psilídeo vetor, Diaphorina citri e a presença do patógeno nas áreas citrícolas é um fator limitante à produção. Tamarixia radiata é o principal agente de controle biológico de D. citri. Assim, os objetivos do presente estudo foram: a) realizar o levantamento populacional de T. radiata nas regiões citrícolas do estado São Paulo; b) caracterizar o policromismo em populações do parasitóide provenientes das principais regiões citrícolas do estado; c) estudar a biologia de T. radiata em condições de laboratório; d) avaliar a capacidade de parasitismo em diferentes temperaturas; e) determinar, mediante liberações em pomares cítricos comerciais, a eficiência de T. radiata para o controle de D. citri; f) determinar a ocorrência e efeitos no parasitismo da associação T. radiata - Wolbachia; g) realizar o zoneamento agroecológico de D. citri e T. radiata com base nas exigências térmicas e higrométricas para o estado de São Paulo. As populações de T. radiata coletadas em Itirapina, Pederneiras, Piracicaba e São Carlos apresentaram variações cromáticas em relação à espécie típica, sendo que as regiões ITS1 e ITS2 do rDNA das populações analisadas apresentaram de 98 a 99% de identidade. Assim, estas variações cromáticas estão relacionadas à plasticidade fenotípica intra-específica, própria de populações que se encontram em processo de adaptação ecológica. Em 24 horas, o maior parasitismo foi obtido nas temperaturas de 25 e 30°C. Este parasitóide desenvolveu-se na faixa térmica de 15 a 35°C, sendo que 25°C foi a temperatura mais adequada por proporcionar maior viabilidade do período ovo-adulto e os maiores valores da taxa liquida de reprodução (Ro) e da razão finita de aumento (). No município de Araras, oito dias após a liberação, a porcentagem de parasitismo de T. radiata se manteve entre 51,57 e 72,75%. Nos municípios de Cordeirópolis e Limeira, após três liberações, a porcentagem de parasitismo variou entre 30 e 60%. As populações coletadas em Cafelândia, Ribeirão Bonito e Piracicaba apresentaram infecção múltipla por Wolbachia. O limite térmico inferior de desenvolvimento (Tb) foi de 7,13°C e a constante térmica de 188,7GD. Mediante um Sistema de Informação Geográfica, foram obtidos mapas de distribuição do desenvolvimento de T. radiata e D. citri. Assim, ao longo do ano podem ocorrer, na região norte, de 10 a 13 ciclos de D. citri e de 31 a 35 ciclos de T. radiata; na região nordeste, o número de ciclos pode variar de 6 a 10 e de 24 a 31 para a praga e para o parasitóide, respectivamente; nas regiões sudoeste e sudeste, o número de gerações pode variar de 3 a 10 e de 19 a 31 para D. citri e T. radiata. Verificando estes aspectos da interação T. radiata e D. citri, os dados obtidos no presente trabalho poderão auxiliar para a implementação de um programa de controle biológico, como parte do manejo de D. citri, em regiões ecologicamente distintas do estado de São Paulo. / Since 2004, have been detected in citrus-growing areas of São Paulo, the bacterias that are responsible for the main disease of citrus worldwide, known as greening or huanglongbing. The widespread distribution in Brazil of the vector psyllid, Diaphorina citri and the presence of the pathogen in citrus-growing areas is a limiting factor for production. Tamarixia radiata is the most important biological control agent against D. citri. Therefore, the objectives of this study were to: a) conduct a population survey of T. radiata in the citrus-growing regions of the State of São Paulo; b) characterize polychromism in populations of the parasitoid from the main growing regions in the State of São Paulo; c) study the biology of T. radiata under laboratory conditions; d) evaluate the parasitism capacity at different temperatures; e) determine, by means of releases in commercial citrus orchards, the effectiveness of T. radiata for the control of D. citri; f) determine the occurrence and effects on parasitism of the T. radiata - Wolbachia association; g) prepare an agroecological zoning of D. citri and T. radiata for the State of São Paulo based on their temperature and humidity requirements. T. radiata populations collected in Itirapina, Pederneiras, Piracicaba, and São Carlos showed chromatic variations in relation to the typical species; the ITS1 and ITS2 rDNA regions of the populations analyzed had between 98 and 99% identity. Consequently, these chromatic variations are related to the intraspecific phenotypic plasticity characteristic of populations that are undergoing a process of ecological adaptation. In a 24-hour period, the highest parasitism of T. radiata was obtained at 25 and 30°C. This parasitoid developed in the temperature range from 15 to 35°C; the most suitable temperature was 25°C, since it gave the highest viability for the egg-adult period, and the highest net reproductive rate (Ro) and finite rate of increase values (). In the municipality of Araras, T. radiata parasitism percentage values eight days after release remained between 51.57 and 72.75%. In the areas selected in the municipalities of Cordeirópolis and Limeira, the parasitism percentage of T. radiata after three releases ranged between 30 and 60%. The populations collected in Cafelândia, Ribeirão Bonito, and Piracicaba showed multiple infections by Wolbachia. The parasitoids lower temperature development threshold (Tb) was 7.13°C, with a thermal constant of 188.7 GDD. Distribution maps for T. radiata and D. citri development in the State of São Paulo were obtained by means of a Geographic Information System (GIS). According to those, from 10 to 13 D. citri cycles and from 31 to 35 T. radiata cycles may occur in the northern region over the course of one year; in the northeastern region, the numbers of cycles may vary from 6 to 10 and from 24 to 31 for the pest and the parasitoid, respectively; in the southwest and southeast regions the numbers of generations may vary from 3 to 10 and from 19 to 31 for D. citri and T. radiata. Based on these aspects of the T. radiata × D. citri interaction, the data obtained in this work can be useful for the implement a biological control program as part of D. citri management in ecologically distinct regions of the State of São Paulo.

O objetivo da presente pesquisa foi fornecer subsídios, visando ao controle de Diatraea saccharalis (Fabricius, 1794) em milho, com o parasitóide de ovos Trichogramma galloi Zucchi, 1988. Foram realizados estudos do parasitóide, incluindo seleção de linhagens, efeito de fatores abióticos (temperatura e alimento) sobre parâmetros biológicos e de parasitismo, bem como comportamento de postura de D. saccharalis em milho. A seleção de linhagens foi conduzida nas temperaturas de 25 e 30°C e o efeito da temperatura sobre a longevidade e a capacidade de parasitismo foi estudado em 15 condições térmicas (na faixa de 10 a 38°C). O efeito de quatro tipos de alimentos foi avaliado sobre a longevidade e a capacidade de parasitismo. O comportamento de postura de D. saccharalis foi observado em dois níveis de infestação (dois e dez casais por planta). Constatou-se que a linhagem G16080 foi a mais adequada para liberações visando ao controle de D. saccharalis, com base na capacidade de parasitismo e na duração do ciclo e por ter apresentado desempenho equivalente na faixa de 25 a 30°C. A maior capacida de de parasitismo de T. galloi linhagem G16080 ocorreu entre 20 e 28°C, embora ten ha havido parasitismo em todas as temperaturas na faixa de 10 a 38ºC. Não houve correlação entre a longevidade e parasitismo, havendo uma concentração deste parasitismo quando o inseto viveu menos. A presença do hospedeiro interferiu na longevidade de T. galloi linhagem G16080. Considerando-se o parasitismo, mel puro e a solução de pólen são os alimentos mais adequados para T. galloi linhagem G16080. Com ou sem o hospedeiro, mel + pólen foi o alimento que proporcionou a maior longevidade para T. galloi linhagem G16080. Independentemente do nível populacional de D. saccharalis, houve uma acentuada preferência pela região do colmo para postura, em relação às folhas de milho de 45 dias de idade, o que pode definir a amostragem e a forma de liberação do parasitóide. / The objective of this study was to provide information aiming to control Diatraea saccharalis (Fabricius, 1794) in corn with the egg parasitoid Trichogramma galloi Zucchi, 1988. Studies realized on the parasitoid included strain selection; effect of abiotic factors (temperature and food) on biological parameters and parasitism as well as oviposition behavior of D. saccharalis in corn. Strain selection was conducted at a temperature of 25 and 30°C and the effect of temper ature on longevity and parasitism capacity was studied at 15 temperature conditions (in the range of 10 to 38°C). The effect of four types of food sources was evaluated on longevity and parasitism capacity. The oviposition behavior of D. saccharalis was observed in two levels of infestation (two and ten couples per plant). It was verified that the strain G16080 was more suitable for release with the aim to control D. saccharalis based on the parasitism capacity and duration of the life cycle and having equivalent performance at a temperature range of 25 to 30°C. The highest rate of parasitism by the T. galloi strain G16080 occurred between 20 and 28°C, althoug h there was parasitism in all other temperature ranges of 10 to 38ºC. There was no correlation between longevity and parasitism, with concentration of this parasitism when the insect lived less. The presence of the host interfered with longevity of the T. galloi strain G16080. Considering parasitism, pure honey and the pollen solution are more suitable as food for T. galloi strain G16080. With or without the host, honey + pollen was the food that produced the highest longevity for T. galloi strain G16080. Irrespective of the population level of D. saccharalis, there was a clear preference for oviposition on the stem in relation to 45 day old corn leaves that could define sampling and the form of release of the parasitoid.

No description available.

Chionochloa, a genus of snow tussock grasses native to New Zealand, exhibits pronounced mast seeding. Chionochloa suffers very high levels of pre-dispersal flower and seed predation by three main insects: Eucalyptodiplosis chionochloae, a cecidomyiid midge, which is formally described here; Megacraspedus calamogonus, a gelechiid moth and Diplotoxa similis, a chloropid fly. Seven species of parasitoids that attack these seed predators were discovered. Four species parasitize M. calamogonus (one tachinid fly and three hymenopteran wasps), one parasitizes D. similis (Hymenoptera: Eulophidae) and two parasitize E. chionochloae, (a pteromalid wasp Gastrancistrus sp. and a platygastrid wasp Zelostemma chionochloae, which is given a formal description here). The abundance, predation levels by each of the insect species, and interactions between all the organisms in the community were studied across three elevations at Mount Hutt over three summer seasons. M. calamogonus was most abundant at 450 m altitude during all three seasons. D. similis was most common at 1070 m altitude, while its predation levels peaked in low flowering seasons and decreased in high seasons. E. chionochloae was abundant in all three altitudes and increased its predation levels with increasing flowering intensity. E. chionochloae was confirmed to use prolonged diapause of at least three years. Prolonged diapause was also confirmed in its two parasitoids. Chionochloa plants were manipulated with various treatments to test the effect on diapause in E. chionochloae and its two parasitoids. Treatments included plant warming, root pruning, gibberellic acid sprayed on the plants and combinations of these treatments. All three insects changed their emergence in response to some treatments and therefore it was suggested that combined with risk-spreading diapause, they may use some predicting to emerge from prolonged diapause. E. chionochloae control their diapause following some of the cues that Chionochloa use for flowering, while Z. chionochloae and Gastrancistrus in some cases follow their host’s cues and in others use similar cues as Chionochloa plants. Emergence or diapause predictions differed across elevations and plant species in all three insect seed/flower predators. E. chionochloae had female-biased sex ratios in different populations even after prolonged diapause. There was week evidence that both parasitoid species are female-biased in the first emergence year and male-biased after more than one year in diapause. Therefore it was suggested that diapause is not more costly for females of E. chionochloae and its parasitoid than for males. Females of all three species were not found to be better predictors (i.e, more likely to respond to treatments by not entering extended diapause) than males. The complex interactions of all the organisms in this web are thought to be sensitive to climate, and it was suggested that the global climate change may alter this sensitive system.

O objetivo da presente pesquisa foi fornecer subsídios, visando ao controle de Diatraea saccharalis (Fabricius, 1794) em milho, com o parasitóide de ovos Trichogramma galloi Zucchi, 1988. Foram realizados estudos do parasitóide, incluindo seleção de linhagens, efeito de fatores abióticos (temperatura e alimento) sobre parâmetros biológicos e de parasitismo, bem como comportamento de postura de D. saccharalis em milho. A seleção de linhagens foi conduzida nas temperaturas de 25 e 30°C e o efeito da temperatura sobre a longevidade e a capacidade de parasitismo foi estudado em 15 condições térmicas (na faixa de 10 a 38°C). O efeito de quatro tipos de alimentos foi avaliado sobre a longevidade e a capacidade de parasitismo. O comportamento de postura de D. saccharalis foi observado em dois níveis de infestação (dois e dez casais por planta). Constatou-se que a linhagem G16080 foi a mais adequada para liberações visando ao controle de D. saccharalis, com base na capacidade de parasitismo e na duração do ciclo e por ter apresentado desempenho equivalente na faixa de 25 a 30°C. A maior capacida de de parasitismo de T. galloi linhagem G16080 ocorreu entre 20 e 28°C, embora ten ha havido parasitismo em todas as temperaturas na faixa de 10 a 38ºC. Não houve correlação entre a longevidade e parasitismo, havendo uma concentração deste parasitismo quando o inseto viveu menos. A presença do hospedeiro interferiu na longevidade de T. galloi linhagem G16080. Considerando-se o parasitismo, mel puro e a solução de pólen são os alimentos mais adequados para T. galloi linhagem G16080. Com ou sem o hospedeiro, mel + pólen foi o alimento que proporcionou a maior longevidade para T. galloi linhagem G16080. Independentemente do nível populacional de D. saccharalis, houve uma acentuada preferência pela região do colmo para postura, em relação às folhas de milho de 45 dias de idade, o que pode definir a amostragem e a forma de liberação do parasitóide. / The objective of this study was to provide information aiming to control Diatraea saccharalis (Fabricius, 1794) in corn with the egg parasitoid Trichogramma galloi Zucchi, 1988. Studies realized on the parasitoid included strain selection; effect of abiotic factors (temperature and food) on biological parameters and parasitism as well as oviposition behavior of D. saccharalis in corn. Strain selection was conducted at a temperature of 25 and 30°C and the effect of temper ature on longevity and parasitism capacity was studied at 15 temperature conditions (in the range of 10 to 38°C). The effect of four types of food sources was evaluated on longevity and parasitism capacity. The oviposition behavior of D. saccharalis was observed in two levels of infestation (two and ten couples per plant). It was verified that the strain G16080 was more suitable for release with the aim to control D. saccharalis based on the parasitism capacity and duration of the life cycle and having equivalent performance at a temperature range of 25 to 30°C. The highest rate of parasitism by the T. galloi strain G16080 occurred between 20 and 28°C, althoug h there was parasitism in all other temperature ranges of 10 to 38ºC. There was no correlation between longevity and parasitism, with concentration of this parasitism when the insect lived less. The presence of the host interfered with longevity of the T. galloi strain G16080. Considering parasitism, pure honey and the pollen solution are more suitable as food for T. galloi strain G16080. With or without the host, honey + pollen was the food that produced the highest longevity for T. galloi strain G16080. Irrespective of the population level of D. saccharalis, there was a clear preference for oviposition on the stem in relation to 45 day old corn leaves that could define sampling and the form of release of the parasitoid.

Desde 2004 foram detectadas, nas áreas citrícolas paulistas, as bactérias responsáveis pela principal doença de citros no mundo, o huanglongbing ou greening. A ampla distribuição no Brasil do psilídeo vetor, Diaphorina citri e a presença do patógeno nas áreas citrícolas é um fator limitante à produção. Tamarixia radiata é o principal agente de controle biológico de D. citri. Assim, os objetivos do presente estudo foram: a) realizar o levantamento populacional de T. radiata nas regiões citrícolas do estado São Paulo; b) caracterizar o policromismo em populações do parasitóide provenientes das principais regiões citrícolas do estado; c) estudar a biologia de T. radiata em condições de laboratório; d) avaliar a capacidade de parasitismo em diferentes temperaturas; e) determinar, mediante liberações em pomares cítricos comerciais, a eficiência de T. radiata para o controle de D. citri; f) determinar a ocorrência e efeitos no parasitismo da associação T. radiata - Wolbachia; g) realizar o zoneamento agroecológico de D. citri e T. radiata com base nas exigências térmicas e higrométricas para o estado de São Paulo. As populações de T. radiata coletadas em Itirapina, Pederneiras, Piracicaba e São Carlos apresentaram variações cromáticas em relação à espécie típica, sendo que as regiões ITS1 e ITS2 do rDNA das populações analisadas apresentaram de 98 a 99% de identidade. Assim, estas variações cromáticas estão relacionadas à plasticidade fenotípica intra-específica, própria de populações que se encontram em processo de adaptação ecológica. Em 24 horas, o maior parasitismo foi obtido nas temperaturas de 25 e 30°C. Este parasitóide desenvolveu-se na faixa térmica de 15 a 35°C, sendo que 25°C foi a temperatura mais adequada por proporcionar maior viabilidade do período ovo-adulto e os maiores valores da taxa liquida de reprodução (Ro) e da razão finita de aumento (). No município de Araras, oito dias após a liberação, a porcentagem de parasitismo de T. radiata se manteve entre 51,57 e 72,75%. Nos municípios de Cordeirópolis e Limeira, após três liberações, a porcentagem de parasitismo variou entre 30 e 60%. As populações coletadas em Cafelândia, Ribeirão Bonito e Piracicaba apresentaram infecção múltipla por Wolbachia. O limite térmico inferior de desenvolvimento (Tb) foi de 7,13°C e a constante térmica de 188,7GD. Mediante um Sistema de Informação Geográfica, foram obtidos mapas de distribuição do desenvolvimento de T. radiata e D. citri. Assim, ao longo do ano podem ocorrer, na região norte, de 10 a 13 ciclos de D. citri e de 31 a 35 ciclos de T. radiata; na região nordeste, o número de ciclos pode variar de 6 a 10 e de 24 a 31 para a praga e para o parasitóide, respectivamente; nas regiões sudoeste e sudeste, o número de gerações pode variar de 3 a 10 e de 19 a 31 para D. citri e T. radiata. Verificando estes aspectos da interação T. radiata e D. citri, os dados obtidos no presente trabalho poderão auxiliar para a implementação de um programa de controle biológico, como parte do manejo de D. citri, em regiões ecologicamente distintas do estado de São Paulo. / Since 2004, have been detected in citrus-growing areas of São Paulo, the bacterias that are responsible for the main disease of citrus worldwide, known as greening or huanglongbing. The widespread distribution in Brazil of the vector psyllid, Diaphorina citri and the presence of the pathogen in citrus-growing areas is a limiting factor for production. Tamarixia radiata is the most important biological control agent against D. citri. Therefore, the objectives of this study were to: a) conduct a population survey of T. radiata in the citrus-growing regions of the State of São Paulo; b) characterize polychromism in populations of the parasitoid from the main growing regions in the State of São Paulo; c) study the biology of T. radiata under laboratory conditions; d) evaluate the parasitism capacity at different temperatures; e) determine, by means of releases in commercial citrus orchards, the effectiveness of T. radiata for the control of D. citri; f) determine the occurrence and effects on parasitism of the T. radiata - Wolbachia association; g) prepare an agroecological zoning of D. citri and T. radiata for the State of São Paulo based on their temperature and humidity requirements. T. radiata populations collected in Itirapina, Pederneiras, Piracicaba, and São Carlos showed chromatic variations in relation to the typical species; the ITS1 and ITS2 rDNA regions of the populations analyzed had between 98 and 99% identity. Consequently, these chromatic variations are related to the intraspecific phenotypic plasticity characteristic of populations that are undergoing a process of ecological adaptation. In a 24-hour period, the highest parasitism of T. radiata was obtained at 25 and 30°C. This parasitoid developed in the temperature range from 15 to 35°C; the most suitable temperature was 25°C, since it gave the highest viability for the egg-adult period, and the highest net reproductive rate (Ro) and finite rate of increase values (). In the municipality of Araras, T. radiata parasitism percentage values eight days after release remained between 51.57 and 72.75%. In the areas selected in the municipalities of Cordeirópolis and Limeira, the parasitism percentage of T. radiata after three releases ranged between 30 and 60%. The populations collected in Cafelândia, Ribeirão Bonito, and Piracicaba showed multiple infections by Wolbachia. The parasitoids lower temperature development threshold (Tb) was 7.13°C, with a thermal constant of 188.7 GDD. Distribution maps for T. radiata and D. citri development in the State of São Paulo were obtained by means of a Geographic Information System (GIS). According to those, from 10 to 13 D. citri cycles and from 31 to 35 T. radiata cycles may occur in the northern region over the course of one year; in the northeastern region, the numbers of cycles may vary from 6 to 10 and from 24 to 31 for the pest and the parasitoid, respectively; in the southwest and southeast regions the numbers of generations may vary from 3 to 10 and from 19 to 31 for D. citri and T. radiata. Based on these aspects of the T. radiata × D. citri interaction, the data obtained in this work can be useful for the implement a biological control program as part of D. citri management in ecologically distinct regions of the State of São Paulo.

Ao longo do processo evolutivo, parasitóides desenvolveram a habilidade de manipular inúmeros processos fisiológicos de seus hospedeiros. Entre os efeitos induzidos pelo parasitismo, incluem-se alterações no ambiente nutricional, sistema endócrino e imunológico do hospedeiro, além da manipulação da capacidade de síntese protéica de seus tecidos. O tecido adiposo é o principal órgão de síntese de proteínas em insetos e a manipulação de sua atividade é de fundamental importância para o sucesso do parasitismo. Este trabalho teve por objetivo avaliar a expressão gênica do tecido adiposo de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) parasitada por Cotesia flavipes (Cameron) (Hymenoptera: Braconidae), visando à obtenção de dados para o desenvolvimento de novas estratégias de controle da broca da cana-deaçúcar. Lagartas de D. saccharalis na pré-muda para o último ínstar foram separadas, sendo parte delas sujeita ao parasitismo por C. flavipes, enquanto outra foi mantida como controle. O tecido adiposo de hospedeiros sadios e parasitados foi coletado 1, 3, 5, 7 e 9 dias após o parasitismo e submetido a extração de RNA, síntese de cDNA e análise de expressão gênica diferencial via DD-PCR (Differential Display PCR). Fragmentos expressos diferencialmente entre os tratamentos foram selecionados, clonados e sequenciados. As sequências obtidas foram comparadas àquelas disponíveis em banco de dados. C. flavipes induziu alterações na expressão de um transcrito codificador de uma proteína de armazenamento logo no início do parasitismo. As proteínas de armazenamento, ou hexamerinas, apresentam grande importância no desenvolvimento de insetos, atuando como fonte de aminoácidos a serem utilizados pela pupa e adulto durante a metamorfose e reprodução. Dada a importância desta proteína, o cDNA responsável por sua codificação foi caracterizado via extensão das porções terminais 5 e 3. A sequência completa do cDNA apresentou 2.353 pb, e o polipeptídeo deduzido, 745 aminoácidos. O conteúdo de metionina e aminoácidos aromáticos, bem como a análise filogenética realizada, indicaram que a hexamerina identificada em D. saccharalis é uma proteína rica em metionina. A identificação e caracterização da hexamerina de D.saccharalis podem representar o primeiro passo para o desenvolvimento de novos métodos de controle da broca da cana-de-açúcar, baseados nas interações hospedeiro-parasitóide / During evolution, parasitoids evolved the ability to manipulate the physiology of their hosts. Among the common effects of the parasitism, hosts may show an alteration of their hemolymph composition (parasitoid nutritional environment), endocrine and immune systems, and protein synthesis activity of host tissues. The fat body is the main organ of protein synthesis of insects and the manipulation of its activity is key for parasitoid successful development. The goal of this study was to evaluate the effects of parasitization by Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) on the gene expression activity of the fat body of Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), to provide additional information on key regulatory pathways to control host metabolism as a step forward for the development of new control strategies based on parasitoid host regulation strategies. Fifth-instars of D. saccharalis at the head slippage stage were isolated and separated in two different groups. One group was individually parasitized by C. flavipes, and the other was kept as control. The fat bodies of parasitized and non-parasitized hosts were collected 1, 3, 5, 7 and 9 days after parasitism, subjected to RNA extraction, cDNA synthesis and differential gene expression analysis by DD-PCR (Differential Display PCR). Transcripts that were differentially expressed between treatments were selected, cloned and sequenced. The obtained sequences were compared to those available at the NCBi data bank. C. flavipes up-regulated the expression of a transcript enconding for a storage protein soon after parasitization. The storage proteins, or hexamerins, are essential for insect development, acting as a reservoir of aminoacids and nitrogen to be used by the pupa and adults during metamorphosis and reproduction. Due to the importance of these proteins, the cDNA encoding this protein was characterized by the amplification of 5 and 3 terminal ends. The complete cDNA has 2,353 bp and the deduced aminoacid sequence is 745 aa long. The methionine and aromatic aminoacids content, as well as phylogenetic analysis, indicated that the hexamerin identified in D. saccharalis is a methionine-rich protein. The identification and characterization of the hexamerin identified in D. saccharalis is the first step towards to the development of new control strategies based on host-parasitoid interactions.

Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L. (Haloragaceae), and Cabomba caroliniana Gray (Cabombaceae). Despite the high probability of invasion, facilitated by vectors and suitable climate, South Africa’s rich indigenous submerged aquatic flora may be preventing the establishment of these submerged invasive species. Studies on the competitive interactions between a common indigenous submerged macrophytes, Lagarosiphon major (Roxb.) (Hydrocharitaceae) and M.spicatum, an invasive native to Eurasia, were conducted to ascertain which conditions influence competitive superiority. High sediment nutrient conditions significantly increased the growth rate and competitive ability of both species, while clay sediments significantly increased the competitive ability of L. major over M. spicatum, but sandy sediments improved the competitive ability of M. spicatum. These results highlighted the dynamic changes in competition between submerged species driven by abiotic factors, but did not take into consideration the effect that herbivory, a biotic factor, could have on competition between the two species. The effect of herbivory by phytophagous insects of submerged plant species has been regarded as negligible. To find out what this effect is, multiple field surveys were undertaken throughout South Africa to find natural enemies of indigenous Lagarosiphon species with the aim of identifying such species, and quantifying their influence on plant growth dynamics. Several new phytophagous species were recorded for the first time. An ephydrid fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae) was ascertained to be the most ubiquitous and abundant species associated with L. major in South Africa. The influence of herbivory by this fly on the competitive ability of L. major in the presence of M. spicatum was investigated using an inverse linear model, which showed that herbivory by H. lagarosiphon reduced the competitive ability of L. major by approximately five times in favour of M. spicatum. This study served to highlight the importance of herbivory as a driver of submerged aquatic plant dynamics. Current ecological theory emphasises the importance of investigating beyond plant-herbivore interactions, by including multitrophic interactions in community dynamics. Therefore, the potential of parasitism by a parasitoid wasp, Chaenusa luteostigma sp. n. Achterberg (Hymenoptera: Braconidae: Alysiinae) on H. lagarosiphon to shift the competitive interactions between the two plant species was also examined. The addition of the parasitoid reduced the effect of herbivory by the fly on L. major by half, thereby shifting the competitive balance in favour of L. major over M. spicatum. This study provides valuable insight into a selection of drivers of submerged macrophyte assemblages of South Africa. It highlights the precarious position of South African freshwater systems with regard to the potential invasion by damaging submerged invasive species. It also provides interesting insights into the effect of competition, herbivory and parasitism on the establishment and spread of species within submerged freshwater systems. Understanding the different influences could assist managers and policy makers to make validated decisions ensuring the integrity of South African freshwater systems.

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