Thesis (Ph.D.) -- University of Adelaide, Dept. of Entomology, Waite Agricultural Research Institute, 1978.

Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularmente conhecida como faveiro, fava d\'anta ou faveleiro, é uma espécie nativa do Cerrado brasileiro, que apresenta registros de ocorrência por todo o Brasil Central. Sua principal importância econômica está associada às elevadas concentrações de rutina, um flavonóide alvo de muitos estudos farmacológicos e de largo emprego na indústria farmacêutica, sendo esta a segunda espécie mais utilizada como fonte de rutina no mercado mundial. Apesar do amplo uso econômico, sua exploração não apresenta características agrícolas, sendo realizada por vias extrativistas. Além disso, há carência de informações sobre sua biologia, o que torna a exploração um fator de risco à conservação. Há poucos estudos relacionados à sua composição química de seus órgãos e tecidos, além disso, estudos de germinação in vitro para obtenção de calos, suspensões celulares e clones não apresentaram sucesso. Este trabalho teve por objetivo desenvolver uma detalhada investigação da composição flavonoídica de folhas, flores, frutos, madeira, cascas, plântulas, embriões, exsudados radiculares de plântulas, e calos originados da desdiferenciação de diversos explantes pelo emprego da técnica de cromatografia de alta eficiência com detector de arranjo de diodos acoplado ao espectrômetro de massas, com o intuito de contribuir para uma maior compreensão da composição química de seus órgãos e tecidos, e assim, subsidiar novos estudos sobre a biossíntese de flavonoides, assim como, contribuir para a própria exploração racional dos recursos econômicos inerentes a essa espécie. Os resultados obtidos levam à conclusão de que nos diversos órgãos e tecidos de D. mollis investigados, predominam estereoisômeros de astilbina, rutina e quercitrina. Os calos apresentaram perfil flavonoídico muito simples, contendo apenas pequenas quantidades de apigenina, não sendo viáveis à obtenção de flavonoides de interesse por meio de seu cultivo. Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularmente conhecida como faveiro, fava d\'anta ou faveleiro, é uma espécie nativa do Cerrado brasileiro, que apresenta registros de ocorrência por todo o Brasil Central. Sua principal importância econômica está associada às elevadas concentrações de rutina, um flavonóide alvo de muitos estudos farmacológicos e de largo emprego na indústria farmacêutica, sendo esta a segunda espécie mais utilizada como fonte de rutina no mercado mundial. Alguns artigos acadêmicos reportam a detecção de propriedades tóxicas de extratos metanólicos de D. mollis sobre operárias de Apis mellifera, e atribuem a toxicidade ao flavonóide astilbina (3-β-Ο/-rhamnosideo de 5,7,3’,4’-tetraidroxi-2,3-diidroflavonol) isolado dos pedúnculos e flores. Seus resultados indicam que a astilbina reduziu a sobrevivência média das abelhas tratadas. Também é atribuída a astilbina a atividade inibidora sobre o desenvolvimento de larvas de Anticarsia gemmatalis Hübner (Lepdoptera: Noctuidae) e Spodoptera frugiperda Smith (Lepdoptara: Noctuidae), relatando redução do peso corporal durante a fase larval e, prolongamento, tanto da fase larval quanto da fase pupal, para as duas espécies de lepidópteros, consideram a possibilidade de uso deste flavonóide como um biopesticida. Neste estudo, foram testadas as interferências de extratos flavonoídicos de diversos órgãos de D. mollis sobre o forrageio e o ciclo de vida de lagartas de Spodoptera frugiperda (Lepidoptera: Noctuidae) e de adultos de Sitophilus oryzae (Coleoptera: Curculionidae). Nenhum resultado negativo estatisticamente significativo foi observado no forrageio das duas espécies em questão. Tal resultado pode ser devido a uma tolerância desses animais aos flavonoides majoritários encontrados nos extratos, astilbina, rutina e quercitrina, ou ainda a mecanismos de detoxificação. / Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularly known as faveiro, fava d\'anta or faveleiro, is a native species of the Brazilian Cerrado, which has records of occurrence throughout the Central Brazil. Its main economic importance is associated with high concentrations of rutin, a flavonoid target of many pharmacological studies and widespread use in the pharmaceutical industry. D. mollis is the second most commonly used plant species as a source of rutin in the global market. Despite their broad economic use, their exploitation occurs in a very primitive way. In addition, there is no subsidiary information about their biology, which makes exploring this species a risk factor for its conservation. There are few studies that deals with the chemical composition of D. mollis organs and tissues, in addition, in vitro germination studies to obtain calluses, cell suspensions and clones showed no success. This work aimed to develop a detailed research flavonoid composition of leaves, flowers, fruits, wood, bark, seedlings, embryos, seedlings root exudates, callus using high performance liquid chromatography with diode array detector coupled to a mass spectrometer in order to contribute to a greater understanding of the chemical composition of their organs and tissues, and thus support new studies on flavonoid biosynthesis, as well as contribute to the very rational exploitation the financial resources inherent in this species. The principal constituents found were stereoisomers of astilbin, rutin and quercitrin. The callus culture presented a very simple flavonoid profile containing only small amounts of apigenin. Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularly known as faveiro, fava d\'anta or faveleiro, is a native species of the Brazilian Cerrado, which has occurrence records throughout the Central Brazil. Its main economic importance is associated with high concentrations of rutin, a flavonoid target of many pharmacological studies and widespread use in the pharmaceutical industry, which is the second species most commonly used as a source of rutin in the world market. Some scientific papers report toxic activities of methanol extracts of D. mollis on Apis mellifera of workers, and attribute the toxicity astilbin flavonoid (3-β-Ο-rhamnoside of 5,7,3’,4’-tetraidroxi- 2,3-diidroflavonol) isolated from the stems and flowers of this species. These results suggest that astilbin reduced the mean survival of the treated bees. Also is attributed to astilbin the inhibitory activity against the development of Anticarsia gemmatalis Hübner (Lepdoptera: Noctuidae) larvae and Spodoptera frugiperda Smith (Lepdoptara: Noctuidae), reporting body weight loss during the larval stage and extending both larval and pupal stage for the two Lepidopterans. These results suggests the use of astilbin as a biopesticide. In the present study, was tested the interference of the flavonoid extracts from several D. mollis parts on the foraging and life cycle of both Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae and adults of Sitophilus oryzae (Coleoptera: Curculionidae). No statistically significant negative result was observed in foraging of both species concerned. This result may be due to a tolerance of these species to flavonoids majorly found in D. mollis extracts, astilbin, rutin and quercitrin, or due detoxification mechanisms.

Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularmente conhecida como faveiro, fava d\'anta ou faveleiro, é uma espécie nativa do Cerrado brasileiro, que apresenta registros de ocorrência por todo o Brasil Central. Sua principal importância econômica está associada às elevadas concentrações de rutina, um flavonóide alvo de muitos estudos farmacológicos e de largo emprego na indústria farmacêutica, sendo esta a segunda espécie mais utilizada como fonte de rutina no mercado mundial. Apesar do amplo uso econômico, sua exploração não apresenta características agrícolas, sendo realizada por vias extrativistas. Além disso, há carência de informações sobre sua biologia, o que torna a exploração um fator de risco à conservação. Há poucos estudos relacionados à sua composição química de seus órgãos e tecidos, além disso, estudos de germinação in vitro para obtenção de calos, suspensões celulares e clones não apresentaram sucesso. Este trabalho teve por objetivo desenvolver uma detalhada investigação da composição flavonoídica de folhas, flores, frutos, madeira, cascas, plântulas, embriões, exsudados radiculares de plântulas, e calos originados da desdiferenciação de diversos explantes pelo emprego da técnica de cromatografia de alta eficiência com detector de arranjo de diodos acoplado ao espectrômetro de massas, com o intuito de contribuir para uma maior compreensão da composição química de seus órgãos e tecidos, e assim, subsidiar novos estudos sobre a biossíntese de flavonoides, assim como, contribuir para a própria exploração racional dos recursos econômicos inerentes a essa espécie. Os resultados obtidos levam à conclusão de que nos diversos órgãos e tecidos de D. mollis investigados, predominam estereoisômeros de astilbina, rutina e quercitrina. Os calos apresentaram perfil flavonoídico muito simples, contendo apenas pequenas quantidades de apigenina, não sendo viáveis à obtenção de flavonoides de interesse por meio de seu cultivo. Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularmente conhecida como faveiro, fava d\'anta ou faveleiro, é uma espécie nativa do Cerrado brasileiro, que apresenta registros de ocorrência por todo o Brasil Central. Sua principal importância econômica está associada às elevadas concentrações de rutina, um flavonóide alvo de muitos estudos farmacológicos e de largo emprego na indústria farmacêutica, sendo esta a segunda espécie mais utilizada como fonte de rutina no mercado mundial. Alguns artigos acadêmicos reportam a detecção de propriedades tóxicas de extratos metanólicos de D. mollis sobre operárias de Apis mellifera, e atribuem a toxicidade ao flavonóide astilbina (3-β-Ο/-rhamnosideo de 5,7,3’,4’-tetraidroxi-2,3-diidroflavonol) isolado dos pedúnculos e flores. Seus resultados indicam que a astilbina reduziu a sobrevivência média das abelhas tratadas. Também é atribuída a astilbina a atividade inibidora sobre o desenvolvimento de larvas de Anticarsia gemmatalis Hübner (Lepdoptera: Noctuidae) e Spodoptera frugiperda Smith (Lepdoptara: Noctuidae), relatando redução do peso corporal durante a fase larval e, prolongamento, tanto da fase larval quanto da fase pupal, para as duas espécies de lepidópteros, consideram a possibilidade de uso deste flavonóide como um biopesticida. Neste estudo, foram testadas as interferências de extratos flavonoídicos de diversos órgãos de D. mollis sobre o forrageio e o ciclo de vida de lagartas de Spodoptera frugiperda (Lepidoptera: Noctuidae) e de adultos de Sitophilus oryzae (Coleoptera: Curculionidae). Nenhum resultado negativo estatisticamente significativo foi observado no forrageio das duas espécies em questão. Tal resultado pode ser devido a uma tolerância desses animais aos flavonoides majoritários encontrados nos extratos, astilbina, rutina e quercitrina, ou ainda a mecanismos de detoxificação. / Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularly known as faveiro, fava d\'anta or faveleiro, is a native species of the Brazilian Cerrado, which has records of occurrence throughout the Central Brazil. Its main economic importance is associated with high concentrations of rutin, a flavonoid target of many pharmacological studies and widespread use in the pharmaceutical industry. D. mollis is the second most commonly used plant species as a source of rutin in the global market. Despite their broad economic use, their exploitation occurs in a very primitive way. In addition, there is no subsidiary information about their biology, which makes exploring this species a risk factor for its conservation. There are few studies that deals with the chemical composition of D. mollis organs and tissues, in addition, in vitro germination studies to obtain calluses, cell suspensions and clones showed no success. This work aimed to develop a detailed research flavonoid composition of leaves, flowers, fruits, wood, bark, seedlings, embryos, seedlings root exudates, callus using high performance liquid chromatography with diode array detector coupled to a mass spectrometer in order to contribute to a greater understanding of the chemical composition of their organs and tissues, and thus support new studies on flavonoid biosynthesis, as well as contribute to the very rational exploitation the financial resources inherent in this species. The principal constituents found were stereoisomers of astilbin, rutin and quercitrin. The callus culture presented a very simple flavonoid profile containing only small amounts of apigenin. Dimorphandra mollis Benth. (Fabaceae - Caesalpinioideae), popularly known as faveiro, fava d\'anta or faveleiro, is a native species of the Brazilian Cerrado, which has occurrence records throughout the Central Brazil. Its main economic importance is associated with high concentrations of rutin, a flavonoid target of many pharmacological studies and widespread use in the pharmaceutical industry, which is the second species most commonly used as a source of rutin in the world market. Some scientific papers report toxic activities of methanol extracts of D. mollis on Apis mellifera of workers, and attribute the toxicity astilbin flavonoid (3-β-Ο-rhamnoside of 5,7,3’,4’-tetraidroxi- 2,3-diidroflavonol) isolated from the stems and flowers of this species. These results suggest that astilbin reduced the mean survival of the treated bees. Also is attributed to astilbin the inhibitory activity against the development of Anticarsia gemmatalis Hübner (Lepdoptera: Noctuidae) larvae and Spodoptera frugiperda Smith (Lepdoptara: Noctuidae), reporting body weight loss during the larval stage and extending both larval and pupal stage for the two Lepidopterans. These results suggests the use of astilbin as a biopesticide. In the present study, was tested the interference of the flavonoid extracts from several D. mollis parts on the foraging and life cycle of both Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae and adults of Sitophilus oryzae (Coleoptera: Curculionidae). No statistically significant negative result was observed in foraging of both species concerned. This result may be due to a tolerance of these species to flavonoids majorly found in D. mollis extracts, astilbin, rutin and quercitrin, or due detoxification mechanisms.

v, 78 leaves : photo., graphs, tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, Waite Agricultural Research Institute, 1978

Plusieurs insectes se développant dans des milieux nutritionnellement déficients vivent en symbiose durable avec des bactéries intracellulaires (endosymbiotes) qui complémentent leur alimentation et améliorent leur pouvoir adaptatif. Alors que ces associations ont été largement étudiées sur les plans physiologiques et évolutifs, peu de travaux se sont consacrés à l’étude des mécanismes impliqués dans la tolérance et le contrôle des endosymbiotes par l’hôte. L’objectif de cette thèse est d’étudier, chez les charançons des céréales du genre Sitophilus, les particularités moléculaires et immunitaires du bactériome, un organe que l’insecte développe pour héberger les symbiotes et les isoler de sa réponse immunitaire systémique. Le bactériome du charançon exprime une réponse immunitaire modulée : des études transcriptomiques ont montré que les effecteurs de l’immunité sont peu exprimés dans cet organe, à l’exception d’un gène codant un peptide antimicrobien, la coléoptéricine A. Cette dernière interagit avec les endosymbiotes et participe à leur confinement intracellulaire. Dans une première partie, j’ai montré avec une approche d’interférence à l’ARN que l’expression du gène colA serait contrôlée par un système original qui impliquerait les gènes relish et tollip. Cette régulation « interne » au bactériome semble assurer le maintien des endosymbiotes et l’homéostasie de l’organe. Afin de comprendre comment le bactériome répond à une infection par les bactéries exogènes, j’ai suivi par RT-qPCR l’expression de gènes effecteurs de l’immunité dans le bactériome après injection systémique de bactéries à Gram positif ou négatif. Ceci a mis en évidence une réponse « externe », induite en cas d’infection, et qui aurait un rôle de protection des endosymbiotes contre les bactéries exogènes. Enfin, je me suis consacré à l’étude des changements de régulation accompagnant le passage du stade larvaire au stade adulte, marqué par une symbiose très dynamique. Le nombre d’endosymbiotes augmente fortement pendant les premiers jours de vie imaginale, puis diminue jusqu’à leur élimination complète par recyclage autophagique. Une analyse RNAseq a permis d’identifier les voies de signalisation dont l’activité accompagne cette dynamique. Une approche de RT-qPCR a également montré que l’immunité du bactériome est maintenue à un faible niveau d’activation pendant tout le processus de recyclage. Ce travail montre qu’au cours de leur évolution, les insectes ont sélectionné plusieurs stratégies pour assurer le maintien et l’ajustement de leur charge endosymbiotique en fonction de leurs besoins physiologiques : une signalisation immunitaire assurerait le confinement intracellulaire des endosymbiotes, et un ensemble de processus cellulaires incluant l’apoptose et l’autophagie semble être en associé aux voies métaboliques pour assurer le contrôle de la dynamique bactérienne et garantir le compromis bénéfice/coût de la symbiose. / Many insect species living on nutritionally unbalanced media depend on intracellular mutualistic bacteria, called obligatory endosymbionts, for their development and reproduction. Endosymbionts are housed in specialized host cells called bacteriocytes, that group together to form the bacteriome organ. Although such associations have been widely investigated on a physiological and evolutionary point of view, little is known about the mechanisms involved in the tolerance and the control of endosymbionts by the host. This work aims at deciphering the molecular and immune specificities of the bacteriome using the model system Sitophilus oryzae, the cereal weevil, and its obligate endosymbiont Sodalis pierantonius. The weevil bacteriome expresses a modulated immune response: transcriptomic studies showed that immune effector genes were lowly expressed despite the massive bacterial presence, with the exception of colA, a gene encoding for Coleoptericin A, an antimicrobial peptide. Coleoptericin A interacts with endosymbionts and participates in their intracellular seclusion. In a first chapter, I used RNA interference to demonstrate that colA gene expression may be controlled by an original system involving the genes relish and tollip. This “internal” regulation for endosymbiont control seems to maintain bacteriome homeostasis. In a second chapter, in order to understand how the bacteriome responds to an infection by exogenous bacteria, I followed up by RT-qPCR the expression of immune effector genes in the bacteriome after injection of Gram positive and Gram negative bacteria. This highlighted an “external” immune response, inducible upon infections, which may enable endosymbiont protection against exogenous intruders. In a third and last chapter, I focused on the regulation changes that accompany the switch from the larval stage to the imaginal stage, the latter being characterized by a very dynamic symbiosis. Endosymbiont load drastically increases during the first days of imaginal life, then rapidly decreases until complete elimination of the bacteria by autophagic recycling. RNAseq analysis allowed the identification of signaling pathways linked to this dynamic. A complementary RT-qPCR approach also showed that bacteriome immunity was laid low during the whole recycling process. This work shows that several strategies have been selected during host-symbiont coevolution to ensure the maintenance of the endosymbionts and the adjustment of their population depending on the insects physiological needs: immunity allows the intracellular seclusion in the bacteriocytes, and cell processes including autophagy and apoptosis are associated to metabolic pathways to control the endosymbiotic dynamics and secure the cost and benefit trade-off of symbiosis.

Algunas plagas causan daños importantes en productos y granos almacenados, lo cual conlleva consecuentemente a pérdidas de producción y calidad en estos productos.Las principales plagas del arroz almacenado en España son, Sitophilus oryzae L. (Coleoptera Curculionidae), Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae), y Cryptolestes pusillus Schönherr (Coleoptera: Cucujidae). Las dos primeras son plagas primarias que atacan directamente el grano y resultan bastante destructivas debido a que sus larvas se alimentan y desarrollan dentro de él. C.pusillus es, sin embargo, una plaga secundaria que se beneficia de granos que ya están dañados y rotos.Actualmente, el uso de fumigantes e insecticidas de síntesis sigue siendo el principal método de lucha para controlar las plagas de almacén, si bien recientemente (dadas las continuas restricciones al uso de agroquímicos) existe un gran interés en la utilización de otras alternativas tales como el control biológico, el almacenamiento a bajas temperaturas, o los tratamientos con calor entre otros.Igualmente muchos productos obtenidos principalmente de plantas y que derivan del metabolismo secundario de las mismas ofrecen una fuente de bioinsecticidas que podrían representar una alternativa ecológica frente a los insecticidas de síntesis ya que su uso masivo e indiscriminado ha ocasionado problemas tales como la aparición de resistencias en determinadas especies de insectos frente a diferentes materias activas, desequilibrios ecológicos y problemas medioambientales sin olvidar el riesgo que entrañan para la salud humana.Con este trabajo se ha pretendido estudiar la actividad plaguicida de los aceites esenciales extraídos de tres plantas: Coriandrum sativum L. (Umbelliferae), Carum carvii L. (Umbelliferae) y Ocimum basilicum L. (Labiatae) y su posterior fraccionamiento para identificar dentro de estos aceites los compuestos químicos responsables de esta actividad insecticida sobre tres plagas de almacén de arroz (S. oryzae, R.dominica y C.pusillus).Del estudio de estos monoterpenoides, linalol, S-carvona y estragol resultaron tener una alta actividad insecticida sobre estas plagas. Sin embargo el E-anetol fue más selectivo para R.dominica y C.pusillus, así como el limoneno, γ-terpineno, geraniol y eucaliptol sólo resultaron activos frente a C.pusillus.Algunos monoterpenoides podrían actuar de sinergistas potenciando la actividad de otros, como podría ser el caso del alcanfor, acetato de geranilo y E-anetol con linalol en R.dominica y C.pusillus, o el caso del metoxicinamaldehido, p-anisaldehido y linalol que pueden tener efecto sinergista sobre el estragol.Este trabajo también abarcó el estudio de un posible modo de acción de estos monoterpenoides, la inhibición de la acetilcolinesterasa, para alcanzar un mayor entendimiento del comportamiento de estas sustancias en el interior del insecto.Así se pudo observar como la mayoría de monoterpenoides estudiados inhibían en cierta medida esta enzima, siendo fenchona, S-carvona y linalol los monoterpenoides que mayor inhibición originaron.Del mismo modo se observó como fenchona, γ-terpineno, geraniol y linalol inhibían competitivamente la acetilcolinesterasa, mientras que S-carvona, estragol y alcanfor producían una inhibición mixta para esta enzima.Sin embargo no se observó inhibición de la acetilcolinesterasa por parte del E-anetol a las concentraciones de monoterpenoides ensayadas.Para completar este trabajo se examinó de igual forma la capacidad que tenían estos bioinsecticidas de generar resistencia en estas tres plagas así como el mecanismo de resistencia implicado en el desarrollo de este proceso. Para ello se fueron seleccionando las poblaciones de insectos mediante la aplicación de los diferentes monoterpenoides a dosis crecientes durante 7 generaciones. De este modo se pudo calcular el factor de resistencia en cada una de las plagas y para cada uno de los monoterpenoides comparando las concentraciones letales 50 de las poblaciones seleccionadas con las poblaciones iniciales (sensibles).A continuación se analizaron tres posibles sistemas de detoxificación enzimáticos gracias al uso de sinergistas para estudiar el mecanismo de resistencia que podría estar involucrado.De tal forma se observó como estos monoterpenoides inducían lentamente resistencias resultando ventajosos en un futuro para el control de estas plagas.Esta Tesis ha englobado un estudio íntegro y profundo de estos insecticidas ecológicos desde la extracción de los aceites esenciales, seguido de la identificación de compuestos puros (CG-EM) con actividad insecticida junto con el estudio de un modo de acción de estos insecticidas, la selección de resistencia en las poblaciones de insectos y los posibles mecanismos de resistencia que pudieran estar implicados en este proceso. / Some pests cause serious damage to stored grains and stored products and consequently production and quality losses in these products.The rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), the lesser grain borer, Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae) and Cryptolestes pusillus Schönherr (Coleoptera: Cucujidae) were the main damaging pests found in stored rice in Spain.S.oryzae and R.dominica are primary pests attacking directly the intact grain and are quite destructive because their larvi feed and develop inside the grain whereas C.pusillus is a secondary pest which benefits from grains previously damaged.At the present time, organic synthetic pesticides are still the main method to control stored grain pests, however, recently (due to restriction in agrochemicals use) there is a great interest in using other altenatives such as biological control, storage at low-temperatures, or heat treatment.Likewise, many products obtained mainly from plants and derived from secondary metabolism have insecticidal activity against insects, such as monoterpenoids, which present a broad variety of bioinsecticide products which could turn out to be an ecologic alternative to synthetic pesticides since the majority of alternative products are not harmful for the human healthy and they become less environmentally damaging, exhibiting a low impact on the environment.In addition, it cannot be ignored the different difficulties related to resistance due to several active compounds from organic pesticides found in some species of insects.With this work, we have considered remarkable to study the insecticide activity of essential oils extracted from three plants: Coriandrum sativum L. (Umbelliferae), Carum carvii L. (Umbelliferae) and Ocimum basilicum L. (Labiatae) and carry out a bioassay-guided fractionation of their essential oils to identify which compounds were responsible for the volatile toxicity shown on three stored rice pests (S. oryzae, R. dominica and C. pusillus).Linalool, S-carvone and estragole turned out to have a high insecticide activity on these pests. Nevertheless E-anetol was more selective to R. dominica and C. pusillus, being only active on C. pusillus limonene, γ-terpinene, geraniol and eucalyptol.Some monoterpenoids were found as synergists, increasing the activity of the other ones, like for instance, camphor, geranyl acetate and E-anethole with linalool in R.dominica and C.pusillus or metoxycinnamaldehyde, p-anysaldehyde and linalool which could activate to estragole.In this work, the inhibition of acetylcholinesterase as a posible mode of action was studied as well, to reach a clear understanding about the action of these products inside the insects.The majority of monoterpenoids inhibited the enzyme acetylcholinesterase being fenchone, S-carvone and linalool the monoterpenoids that produced a higher inhibition.Furthermore, it was observed how fenchone, γ-terpinene, geraniol and linalool showed a competitive inhibition whereas S-carvone, estragole and camphor produced a mixed inhibition for this enzyme. However the enzyme acetylcholinesterase was not inhibited by E-anethole.To finish up this work, the selection for monoterpenoid resistance on these pests as well as the metabolic mechanisms implicated was studied.The resistant strains were selected from susceptible insect populations and survivors were reared separately for each monoterpenoid and successive generations were treated with higher concentrations. These populations were selected until seven times.As a result we could calculate the resistance factor on each pest (comparing lethal concentration 50 values of susceptible and resistant strains).Next, three enzymatic systems detoxifying these monoterpenoids were analysed to study the metabolic mechanism implicated.In this way we could realize that all monoterpenoids induced resistance slowly, concluding that these pesticides will be appropriated to control these pests in the future.This Thesis has concerned a study in depth about ecological insecticides from extraction of essential oils, identification of compounds (GC-MS) with insecticide activity, mode of action and study of resistance and mechanism of insecticide resistance involved in this process.