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.

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.

Xylophagous borers and termites that damage "timber-in-service" cause millions of dollars loss annually throughout mainland Australia. I developed field-based feeding assays with practical relevance to preventative action and remedial treatment of infestations of xylophagous insects in the built environment. Essential to this work is facilitating a high termite risk by maintaining an environment conducive to sustained foraging by termites. Feeding assays conducted in low termite risk areas are unduly prolonged, with inherently erratic termite feeding responses. I successfully developed feeding assays with a high termite risk. To establish whether a physical barrier, retrofitted as a sleeve, could prevent termites from damaging wooden poles, eighty poles were established within Beerburrum State Forest, south-east Queensland, Australia. Poles within sets were interconnected with buried timber to facilitate a high risk to Coptotermes acinaciformis (Froggatt). Mesh sleeves to a depth of 1.5m did not prevent termite damage to the poles. Hoop pine Araucaria cunninghamii Ait. ex D.Don dowels ("dip-sticks") were useful termite monitoring devices on the poles. The depth of foraging by termites has implications for the effectiveness of retrofitted physical and chemical barriers in general. Timber quantity and quality has a pivotal influence on the aggregation of large numbers of feeding termites necessary for baiting work and for producing efficacy data of relevance to the protection of timber-in-service from termites. Seasonal variation in termite foraging was examined. Both C. acinaciformis and Coptotermes lacteus (Froggatt) were more active feeding in summer than in autumn. In general, mass loss followed mean ambient temperature. Suppression of C. acinaciformis feeding responses relative to C. lacteus during summer, particularly during January, is thought to be due to excessive temperatures in the containers attached to infested trees. Termite foraging behaviour and responses to both varying masses of softwood timbers and varying exposure times were investigated. The rate of mass loss was independent of the number of test specimens and appeared linear. Colonies regulate the number of foragers directly according to the mass of susceptible timber available. This phenomenon was exploited throughout the remainder of the thesis. Of particular significance was the considerable intra- and inter-specific variation in susceptibility of softwoods to C. acinaciformis and Mastotermes darwiniensis Froggatt. The sapwoods tested were susceptible, but the heartwoods were generally resistant to damage by termites. These data confirm that termites are discriminating feeders, and some more so than others. A novel methodology, developed to maintain an environment conducive to sustained foraging by termites during field-testing, is presented. Consistency in timber acceptance and susceptibility to termites is considered to be important in determining the frequency of inspection and the success of bait systems. I evaluate the termiticidal activity of the bait toxicants hexaflumuron and chlorfluazuron for the management of the subterranean termite C. acinaciformis in the field. The Sentricon Colony Elimination System with Baitube-devices containing 0.1% and 1% mass/mass (m/m) hexaflumuron bait toxicant in dry wood flour (Recruit) was successful in eliminating field colonies of C. acinaciformis. Similarly, the Exterra Termite Interception and Baiting System with cellulose-acetate powder containing either 0.05% m/m or 0.25% m/m chlorfluazuron (Requiem) eliminated C. acinaciformis. Indicators (including "dip-sticks") used to monitor colony health were reliable. By using C. acinaciformis, which builds mounds (epigeous nests) in northern Australia, I was able to avoid the use of multiple mark-release schemes to verify the effects of the bait toxicant on the termite colonies. Problems with multiple mark-release schemes, used elsewhere in the world, are discussed. I continued the focus on bait quality and placement by evaluating termite responses to two aspects of treated stakes, their attractiveness and their susceptibility. Three experiments were undertaken near Townsville and at Beerburrum, with Coptotermes and Schedorhinotermes. Whilst there were no significant differences in the rate of location and foraging, with respect to treatments, differences in foraging, with respect to C. acinaciformis and Schedorhinotermes seclusus (Hill) were significant. Coptotermes acinaciformis displayed greater foraging site tenacity than S. seclusus at Beerburrum. Increased consumption of bait, due to the addition of a phagostimulant, needs to be observed in the field before an increase in the efficacy of baits in a termite management program can be claimed. In Australia, softwood timbers are extensively used in building construction and are generally highly susceptible to damage by termites. I focussed on field feeding assays to test efficacy of borate-treated softwoods against termites and to define "adequate" protection thresholds. Laboratory and field data reported in the literature were confusing with regard to what constitutes "adequate" protection thresholds. The confusion was compounded by differences in termite species, timber species used and test methodology. Laboratory data indicated a borate loading of 0.5% m/m boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to 5%. Field data generally suggested that borate loadings in excess of 0.5% m/m BAE were required. The main contribution of the work to increasing our understanding of management options for termites in the built environment was in resolving the confusion between laboratory and field data for borate wood-preservatives. These apparently conflicting results were explained by the presence or absence of untreated feeder material in the test environment. In the absence of untreated feeder material, retention of 0.5% BAE provides adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions are required. Furthermore, the retentions required increase with increased amounts of susceptible material. Some termites, Nasutitermes sp. and M. darwiniensis, for example, are borate-tolerant and borate wood-preservatives are not a viable management option. The lack of uniform standards for termite-test methodology and assessment criteria for efficacy across the world is recognized as a difficulty with research into the performance of wood preservatives with termites. The many variables in laboratory and field assays make "prescriptive" standards difficult to recommend. The use of "performance" standards to define efficacy criteria ("adequate" protection) is discussed. Whilst the majority of the work involves subterranean termites ("termites"), I examine the question of how to define a hardwood timber species as "not susceptible" to lyctine beetle damage. Aspects of the biology, behaviour and management of Lyctus brunneus (Stephens) are reviewed and a novel field sampling and testing protocol to establish lyctine susceptibility of timber species is presented. A sound understanding of the biology and behaviour of xylophagous insects in the field is essential to ensure that management options implemented in the built environment have a strong ecological basis. The success of this study in achieving stated aims, the need for further work and the implications for test methodologies in the field with practical relevance to infestations of xylophagous insects in the built environment are discussed.

Xylophagous borers and termites that damage "timber-in-service" cause millions of dollars loss annually throughout mainland Australia. I developed field-based feeding assays with practical relevance to preventative action and remedial treatment of infestations of xylophagous insects in the built environment. Essential to this work is facilitating a high termite risk by maintaining an environment conducive to sustained foraging by termites. Feeding assays conducted in low termite risk areas are unduly prolonged, with inherently erratic termite feeding responses. I successfully developed feeding assays with a high termite risk. To establish whether a physical barrier, retrofitted as a sleeve, could prevent termites from damaging wooden poles, eighty poles were established within Beerburrum State Forest, south-east Queensland, Australia. Poles within sets were interconnected with buried timber to facilitate a high risk to Coptotermes acinaciformis (Froggatt). Mesh sleeves to a depth of 1.5m did not prevent termite damage to the poles. Hoop pine Araucaria cunninghamii Ait. ex D.Don dowels ("dip-sticks") were useful termite monitoring devices on the poles. The depth of foraging by termites has implications for the effectiveness of retrofitted physical and chemical barriers in general. Timber quantity and quality has a pivotal influence on the aggregation of large numbers of feeding termites necessary for baiting work and for producing efficacy data of relevance to the protection of timber-in-service from termites. Seasonal variation in termite foraging was examined. Both C. acinaciformis and Coptotermes lacteus (Froggatt) were more active feeding in summer than in autumn. In general, mass loss followed mean ambient temperature. Suppression of C. acinaciformis feeding responses relative to C. lacteus during summer, particularly during January, is thought to be due to excessive temperatures in the containers attached to infested trees. Termite foraging behaviour and responses to both varying masses of softwood timbers and varying exposure times were investigated. The rate of mass loss was independent of the number of test specimens and appeared linear. Colonies regulate the number of foragers directly according to the mass of susceptible timber available. This phenomenon was exploited throughout the remainder of the thesis. Of particular significance was the considerable intra- and inter-specific variation in susceptibility of softwoods to C. acinaciformis and Mastotermes darwiniensis Froggatt. The sapwoods tested were susceptible, but the heartwoods were generally resistant to damage by termites. These data confirm that termites are discriminating feeders, and some more so than others. A novel methodology, developed to maintain an environment conducive to sustained foraging by termites during field-testing, is presented. Consistency in timber acceptance and susceptibility to termites is considered to be important in determining the frequency of inspection and the success of bait systems. I evaluate the termiticidal activity of the bait toxicants hexaflumuron and chlorfluazuron for the management of the subterranean termite C. acinaciformis in the field. The Sentricon Colony Elimination System with Baitube-devices containing 0.1% and 1% mass/mass (m/m) hexaflumuron bait toxicant in dry wood flour (Recruit) was successful in eliminating field colonies of C. acinaciformis. Similarly, the Exterra Termite Interception and Baiting System with cellulose-acetate powder containing either 0.05% m/m or 0.25% m/m chlorfluazuron (Requiem) eliminated C. acinaciformis. Indicators (including "dip-sticks") used to monitor colony health were reliable. By using C. acinaciformis, which builds mounds (epigeous nests) in northern Australia, I was able to avoid the use of multiple mark-release schemes to verify the effects of the bait toxicant on the termite colonies. Problems with multiple mark-release schemes, used elsewhere in the world, are discussed. I continued the focus on bait quality and placement by evaluating termite responses to two aspects of treated stakes, their attractiveness and their susceptibility. Three experiments were undertaken near Townsville and at Beerburrum, with Coptotermes and Schedorhinotermes. Whilst there were no significant differences in the rate of location and foraging, with respect to treatments, differences in foraging, with respect to C. acinaciformis and Schedorhinotermes seclusus (Hill) were significant. Coptotermes acinaciformis displayed greater foraging site tenacity than S. seclusus at Beerburrum. Increased consumption of bait, due to the addition of a phagostimulant, needs to be observed in the field before an increase in the efficacy of baits in a termite management program can be claimed. In Australia, softwood timbers are extensively used in building construction and are generally highly susceptible to damage by termites. I focussed on field feeding assays to test efficacy of borate-treated softwoods against termites and to define "adequate" protection thresholds. Laboratory and field data reported in the literature were confusing with regard to what constitutes "adequate" protection thresholds. The confusion was compounded by differences in termite species, timber species used and test methodology. Laboratory data indicated a borate loading of 0.5% m/m boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to 5%. Field data generally suggested that borate loadings in excess of 0.5% m/m BAE were required. The main contribution of the work to increasing our understanding of management options for termites in the built environment was in resolving the confusion between laboratory and field data for borate wood-preservatives. These apparently conflicting results were explained by the presence or absence of untreated feeder material in the test environment. In the absence of untreated feeder material, retention of 0.5% BAE provides adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions are required. Furthermore, the retentions required increase with increased amounts of susceptible material. Some termites, Nasutitermes sp. and M. darwiniensis, for example, are borate-tolerant and borate wood-preservatives are not a viable management option. The lack of uniform standards for termite-test methodology and assessment criteria for efficacy across the world is recognized as a difficulty with research into the performance of wood preservatives with termites. The many variables in laboratory and field assays make "prescriptive" standards difficult to recommend. The use of "performance" standards to define efficacy criteria ("adequate" protection) is discussed. Whilst the majority of the work involves subterranean termites ("termites"), I examine the question of how to define a hardwood timber species as "not susceptible" to lyctine beetle damage. Aspects of the biology, behaviour and management of Lyctus brunneus (Stephens) are reviewed and a novel field sampling and testing protocol to establish lyctine susceptibility of timber species is presented. A sound understanding of the biology and behaviour of xylophagous insects in the field is essential to ensure that management options implemented in the built environment have a strong ecological basis. The success of this study in achieving stated aims, the need for further work and the implications for test methodologies in the field with practical relevance to infestations of xylophagous insects in the built environment are discussed.

Xylophagous borers and termites that damage "timber-in-service" cause millions of dollars loss annually throughout mainland Australia. I developed field-based feeding assays with practical relevance to preventative action and remedial treatment of infestations of xylophagous insects in the built environment. Essential to this work is facilitating a high termite risk by maintaining an environment conducive to sustained foraging by termites. Feeding assays conducted in low termite risk areas are unduly prolonged, with inherently erratic termite feeding responses. I successfully developed feeding assays with a high termite risk. To establish whether a physical barrier, retrofitted as a sleeve, could prevent termites from damaging wooden poles, eighty poles were established within Beerburrum State Forest, south-east Queensland, Australia. Poles within sets were interconnected with buried timber to facilitate a high risk to Coptotermes acinaciformis (Froggatt). Mesh sleeves to a depth of 1.5m did not prevent termite damage to the poles. Hoop pine Araucaria cunninghamii Ait. ex D.Don dowels ("dip-sticks") were useful termite monitoring devices on the poles. The depth of foraging by termites has implications for the effectiveness of retrofitted physical and chemical barriers in general. Timber quantity and quality has a pivotal influence on the aggregation of large numbers of feeding termites necessary for baiting work and for producing efficacy data of relevance to the protection of timber-in-service from termites. Seasonal variation in termite foraging was examined. Both C. acinaciformis and Coptotermes lacteus (Froggatt) were more active feeding in summer than in autumn. In general, mass loss followed mean ambient temperature. Suppression of C. acinaciformis feeding responses relative to C. lacteus during summer, particularly during January, is thought to be due to excessive temperatures in the containers attached to infested trees. Termite foraging behaviour and responses to both varying masses of softwood timbers and varying exposure times were investigated. The rate of mass loss was independent of the number of test specimens and appeared linear. Colonies regulate the number of foragers directly according to the mass of susceptible timber available. This phenomenon was exploited throughout the remainder of the thesis. Of particular significance was the considerable intra- and inter-specific variation in susceptibility of softwoods to C. acinaciformis and Mastotermes darwiniensis Froggatt. The sapwoods tested were susceptible, but the heartwoods were generally resistant to damage by termites. These data confirm that termites are discriminating feeders, and some more so than others. A novel methodology, developed to maintain an environment conducive to sustained foraging by termites during field-testing, is presented. Consistency in timber acceptance and susceptibility to termites is considered to be important in determining the frequency of inspection and the success of bait systems. I evaluate the termiticidal activity of the bait toxicants hexaflumuron and chlorfluazuron for the management of the subterranean termite C. acinaciformis in the field. The Sentricon Colony Elimination System with Baitube-devices containing 0.1% and 1% mass/mass (m/m) hexaflumuron bait toxicant in dry wood flour (Recruit) was successful in eliminating field colonies of C. acinaciformis. Similarly, the Exterra Termite Interception and Baiting System with cellulose-acetate powder containing either 0.05% m/m or 0.25% m/m chlorfluazuron (Requiem) eliminated C. acinaciformis. Indicators (including "dip-sticks") used to monitor colony health were reliable. By using C. acinaciformis, which builds mounds (epigeous nests) in northern Australia, I was able to avoid the use of multiple mark-release schemes to verify the effects of the bait toxicant on the termite colonies. Problems with multiple mark-release schemes, used elsewhere in the world, are discussed. I continued the focus on bait quality and placement by evaluating termite responses to two aspects of treated stakes, their attractiveness and their susceptibility. Three experiments were undertaken near Townsville and at Beerburrum, with Coptotermes and Schedorhinotermes. Whilst there were no significant differences in the rate of location and foraging, with respect to treatments, differences in foraging, with respect to C. acinaciformis and Schedorhinotermes seclusus (Hill) were significant. Coptotermes acinaciformis displayed greater foraging site tenacity than S. seclusus at Beerburrum. Increased consumption of bait, due to the addition of a phagostimulant, needs to be observed in the field before an increase in the efficacy of baits in a termite management program can be claimed. In Australia, softwood timbers are extensively used in building construction and are generally highly susceptible to damage by termites. I focussed on field feeding assays to test efficacy of borate-treated softwoods against termites and to define "adequate" protection thresholds. Laboratory and field data reported in the literature were confusing with regard to what constitutes "adequate" protection thresholds. The confusion was compounded by differences in termite species, timber species used and test methodology. Laboratory data indicated a borate loading of 0.5% m/m boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to 5%. Field data generally suggested that borate loadings in excess of 0.5% m/m BAE were required. The main contribution of the work to increasing our understanding of management options for termites in the built environment was in resolving the confusion between laboratory and field data for borate wood-preservatives. These apparently conflicting results were explained by the presence or absence of untreated feeder material in the test environment. In the absence of untreated feeder material, retention of 0.5% BAE provides adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions are required. Furthermore, the retentions required increase with increased amounts of susceptible material. Some termites, Nasutitermes sp. and M. darwiniensis, for example, are borate-tolerant and borate wood-preservatives are not a viable management option. The lack of uniform standards for termite-test methodology and assessment criteria for efficacy across the world is recognized as a difficulty with research into the performance of wood preservatives with termites. The many variables in laboratory and field assays make "prescriptive" standards difficult to recommend. The use of "performance" standards to define efficacy criteria ("adequate" protection) is discussed. Whilst the majority of the work involves subterranean termites ("termites"), I examine the question of how to define a hardwood timber species as "not susceptible" to lyctine beetle damage. Aspects of the biology, behaviour and management of Lyctus brunneus (Stephens) are reviewed and a novel field sampling and testing protocol to establish lyctine susceptibility of timber species is presented. A sound understanding of the biology and behaviour of xylophagous insects in the field is essential to ensure that management options implemented in the built environment have a strong ecological basis. The success of this study in achieving stated aims, the need for further work and the implications for test methodologies in the field with practical relevance to infestations of xylophagous insects in the built environment are discussed.

Xylophagous borers and termites that damage "timber-in-service" cause millions of dollars loss annually throughout mainland Australia. I developed field-based feeding assays with practical relevance to preventative action and remedial treatment of infestations of xylophagous insects in the built environment. Essential to this work is facilitating a high termite risk by maintaining an environment conducive to sustained foraging by termites. Feeding assays conducted in low termite risk areas are unduly prolonged, with inherently erratic termite feeding responses. I successfully developed feeding assays with a high termite risk. To establish whether a physical barrier, retrofitted as a sleeve, could prevent termites from damaging wooden poles, eighty poles were established within Beerburrum State Forest, south-east Queensland, Australia. Poles within sets were interconnected with buried timber to facilitate a high risk to Coptotermes acinaciformis (Froggatt). Mesh sleeves to a depth of 1.5m did not prevent termite damage to the poles. Hoop pine Araucaria cunninghamii Ait. ex D.Don dowels ("dip-sticks") were useful termite monitoring devices on the poles. The depth of foraging by termites has implications for the effectiveness of retrofitted physical and chemical barriers in general. Timber quantity and quality has a pivotal influence on the aggregation of large numbers of feeding termites necessary for baiting work and for producing efficacy data of relevance to the protection of timber-in-service from termites. Seasonal variation in termite foraging was examined. Both C. acinaciformis and Coptotermes lacteus (Froggatt) were more active feeding in summer than in autumn. In general, mass loss followed mean ambient temperature. Suppression of C. acinaciformis feeding responses relative to C. lacteus during summer, particularly during January, is thought to be due to excessive temperatures in the containers attached to infested trees. Termite foraging behaviour and responses to both varying masses of softwood timbers and varying exposure times were investigated. The rate of mass loss was independent of the number of test specimens and appeared linear. Colonies regulate the number of foragers directly according to the mass of susceptible timber available. This phenomenon was exploited throughout the remainder of the thesis. Of particular significance was the considerable intra- and inter-specific variation in susceptibility of softwoods to C. acinaciformis and Mastotermes darwiniensis Froggatt. The sapwoods tested were susceptible, but the heartwoods were generally resistant to damage by termites. These data confirm that termites are discriminating feeders, and some more so than others. A novel methodology, developed to maintain an environment conducive to sustained foraging by termites during field-testing, is presented. Consistency in timber acceptance and susceptibility to termites is considered to be important in determining the frequency of inspection and the success of bait systems. I evaluate the termiticidal activity of the bait toxicants hexaflumuron and chlorfluazuron for the management of the subterranean termite C. acinaciformis in the field. The Sentricon Colony Elimination System with Baitube-devices containing 0.1% and 1% mass/mass (m/m) hexaflumuron bait toxicant in dry wood flour (Recruit) was successful in eliminating field colonies of C. acinaciformis. Similarly, the Exterra Termite Interception and Baiting System with cellulose-acetate powder containing either 0.05% m/m or 0.25% m/m chlorfluazuron (Requiem) eliminated C. acinaciformis. Indicators (including "dip-sticks") used to monitor colony health were reliable. By using C. acinaciformis, which builds mounds (epigeous nests) in northern Australia, I was able to avoid the use of multiple mark-release schemes to verify the effects of the bait toxicant on the termite colonies. Problems with multiple mark-release schemes, used elsewhere in the world, are discussed. I continued the focus on bait quality and placement by evaluating termite responses to two aspects of treated stakes, their attractiveness and their susceptibility. Three experiments were undertaken near Townsville and at Beerburrum, with Coptotermes and Schedorhinotermes. Whilst there were no significant differences in the rate of location and foraging, with respect to treatments, differences in foraging, with respect to C. acinaciformis and Schedorhinotermes seclusus (Hill) were significant. Coptotermes acinaciformis displayed greater foraging site tenacity than S. seclusus at Beerburrum. Increased consumption of bait, due to the addition of a phagostimulant, needs to be observed in the field before an increase in the efficacy of baits in a termite management program can be claimed. In Australia, softwood timbers are extensively used in building construction and are generally highly susceptible to damage by termites. I focussed on field feeding assays to test efficacy of borate-treated softwoods against termites and to define "adequate" protection thresholds. Laboratory and field data reported in the literature were confusing with regard to what constitutes "adequate" protection thresholds. The confusion was compounded by differences in termite species, timber species used and test methodology. Laboratory data indicated a borate loading of 0.5% m/m boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to 5%. Field data generally suggested that borate loadings in excess of 0.5% m/m BAE were required. The main contribution of the work to increasing our understanding of management options for termites in the built environment was in resolving the confusion between laboratory and field data for borate wood-preservatives. These apparently conflicting results were explained by the presence or absence of untreated feeder material in the test environment. In the absence of untreated feeder material, retention of 0.5% BAE provides adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions are required. Furthermore, the retentions required increase with increased amounts of susceptible material. Some termites, Nasutitermes sp. and M. darwiniensis, for example, are borate-tolerant and borate wood-preservatives are not a viable management option. The lack of uniform standards for termite-test methodology and assessment criteria for efficacy across the world is recognized as a difficulty with research into the performance of wood preservatives with termites. The many variables in laboratory and field assays make "prescriptive" standards difficult to recommend. The use of "performance" standards to define efficacy criteria ("adequate" protection) is discussed. Whilst the majority of the work involves subterranean termites ("termites"), I examine the question of how to define a hardwood timber species as "not susceptible" to lyctine beetle damage. Aspects of the biology, behaviour and management of Lyctus brunneus (Stephens) are reviewed and a novel field sampling and testing protocol to establish lyctine susceptibility of timber species is presented. A sound understanding of the biology and behaviour of xylophagous insects in the field is essential to ensure that management options implemented in the built environment have a strong ecological basis. The success of this study in achieving stated aims, the need for further work and the implications for test methodologies in the field with practical relevance to infestations of xylophagous insects in the built environment are discussed.

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.

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.

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