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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The effects of nicotine sequestration on the dynamics of hyperparasitism in a stage-structured model of Manduca sexta and its related parasitoid wasps

Zimmerman, Mark P 01 January 2015 (has links)
Two proposed models will be used to help answer a long observed question in the dynamics of \textit{Manduca sexta} and its related parasitoid wasps-Why is there a large difference in diversity in hyperparasitoid species between tobacco and other related plants such as tomato? Two stage structured differential equation models are presented. The first is a single patch model to study the changes in dynamics that occur between hosts, parasitoids, and hyperparasitoids as the amount of nicotine in the plant increases. The second is a two patch model that allows hyperparasitoids to choose between patches that are nicotine negative (i.e. tomato plants) and nicotine positive (i.e. tobacco plants). Both models will be used to investigate how host nicotine sequestration may impact hyperparasitoid diversity.
12

Patch exploitation by the parasitoids of Plutella xylostella (L.): from individual behaviour to population dynamics /

Wang, Xin-geng. January 2001 (has links) (PDF)
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001. / Includes bibliographical references (leaves 204-230).
13

Basis of host recognition by the larval endoparasitoids : Cotesia sesamiae Cameron and Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) / Obonyo Amos Owino Meshack

Meshack, Obonyo Amos Owino January 2009 (has links)
Host recognition behaviour of two braconid larval parasitoids Cotesia sesamiae and Cotesia flavipes was studied using suitable stemborer hosts [i.e. Busseola fusca for C. sesamiae, and Chilo partellus for C. flavipes] and one non-host [Eldana saccharina]. The wasps displayed similar sequences of behavioural steps when locating their hosts largely depending on their antennae for host recognition and both antennae and tarsi for final host acceptance and oviposition. Tactile and contact chemoreception stimuli from the hosts seem to play a major role in oviposition decision by the parasitoids. In addition, the external morphology and distribution pattern of sensilla present on antennae, tarsi and ovipositor of the parasitoids were examined by scanning electron and optic microscopy after staining with silver nitrate. Three sensillar types were identified on the distal antennomeres: (i) non-porous sensilla trichoidea most probably involved in mechanoreception, (ii) uniporous sensilla chaetica likely to be gustatory and, (iii) multiporous sensilla placodea likely to be olfactory. The tarsi possess a few sensilla chaetica which could be gustatory while the manubrium is likely to be used in detection of vibrations. The distal end of the ovipositor bears numerous multiporous dome-shaped sensilla. Additionally, the ability of the wasps to discriminate between contact cues was studied. When host larvae were washed in distilled water the wasps did not insert their ovipositors. However, ovipositor insertion resumed when washed host or non-host larvae were painted with water extracts of their respective host larvae. The water extracts of the suitable hosts were more attractive to the wasps than those of non-hosts. Similarly, the frass is important in host recognition during short-range examination as those of respective hosts are more intensely antennated than of non-hosts. The parasitoids were able to discriminate the regurgitant of E. saccharina by not antennating the cotton wool ball of this host; while the regurgitant of B. fusca and C. partellus appeared not useful in discriminating between the two species for both parasitoid species. Further analysis suggests the presence of a protein(s) component(s) in the regurgitant possibly responsible for host recognition and oviposition by C. flavipes. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2009.
14

Basis of host recognition by the larval endoparasitoids : Cotesia sesamiae Cameron and Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) / Obonyo Amos Owino Meshack

Meshack, Obonyo Amos Owino January 2009 (has links)
Host recognition behaviour of two braconid larval parasitoids Cotesia sesamiae and Cotesia flavipes was studied using suitable stemborer hosts [i.e. Busseola fusca for C. sesamiae, and Chilo partellus for C. flavipes] and one non-host [Eldana saccharina]. The wasps displayed similar sequences of behavioural steps when locating their hosts largely depending on their antennae for host recognition and both antennae and tarsi for final host acceptance and oviposition. Tactile and contact chemoreception stimuli from the hosts seem to play a major role in oviposition decision by the parasitoids. In addition, the external morphology and distribution pattern of sensilla present on antennae, tarsi and ovipositor of the parasitoids were examined by scanning electron and optic microscopy after staining with silver nitrate. Three sensillar types were identified on the distal antennomeres: (i) non-porous sensilla trichoidea most probably involved in mechanoreception, (ii) uniporous sensilla chaetica likely to be gustatory and, (iii) multiporous sensilla placodea likely to be olfactory. The tarsi possess a few sensilla chaetica which could be gustatory while the manubrium is likely to be used in detection of vibrations. The distal end of the ovipositor bears numerous multiporous dome-shaped sensilla. Additionally, the ability of the wasps to discriminate between contact cues was studied. When host larvae were washed in distilled water the wasps did not insert their ovipositors. However, ovipositor insertion resumed when washed host or non-host larvae were painted with water extracts of their respective host larvae. The water extracts of the suitable hosts were more attractive to the wasps than those of non-hosts. Similarly, the frass is important in host recognition during short-range examination as those of respective hosts are more intensely antennated than of non-hosts. The parasitoids were able to discriminate the regurgitant of E. saccharina by not antennating the cotton wool ball of this host; while the regurgitant of B. fusca and C. partellus appeared not useful in discriminating between the two species for both parasitoid species. Further analysis suggests the presence of a protein(s) component(s) in the regurgitant possibly responsible for host recognition and oviposition by C. flavipes. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2009.
15

Pistas químicas atraem inimigos naturais de larvas de Ascia monuste orseis (Lepidoptera: Pieridae) / Chemical cues attract natural enemies of Ascia monuste orseis (Lepidoptera: Pieridae) larvae

Mariscal, Adriano Affonso, 1980- 03 January 2013 (has links)
Orientador: José Roberto Trigo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T04:31:56Z (GMT). No. of bitstreams: 1 Mariscal_AdrianoAffonso_M.pdf: 5931496 bytes, checksum: beff506193372fed1f1ae62149a3f37d (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Ecologia / Mestre em Biologia Animal
16

Estratégias de parasitismo da vespa parasitóide Cotesia flavipes, Cameron, 1891 (Hymenoptera:Braconidae) / Comparison between three ages of the parasitoid Cotesia flavipes in the parasitism of Diatraea saccharalis

Uehara, Marcia Terumi 26 August 2005 (has links)
Cotesia flavipes é uma vespa endoparasitóide introduzida no Brasil para controlar biologicamente o hospedeiro Diatraea saccharalis, conhecida como a broca da cana-de-açúcar. Estes insetos são criados há mais de trinta anos no Brasil em laboratórios de criação massal. Em épocas de boa produtividade de fêmeas nos laboratórios de criação massal os parasitóides são utilizados logo após a emergência. Porém, em alguns períodos do ano, a produção de insetos apresenta com a razão sexual desviada para machos então, os insetos são utilizados após 24 horas, para tentar garantir a cópula. O objetivo deste trabalho foi comparar a eficiência de C.flavipes de três idades (0, 24 e 48h) no parasitismo de D. saccharalis de 5° instar e com a densidade de 3 hospedeiros. Três hospedeiros foram oferecidos à fêmea parasitóide para que a mesma realizasse as posturas em um curto intervalo de tempo e com densidade fixa. Verificou-se que C. flavipes das três idades foram capazes de parasitar os 3 hospedeiros oferecidos para oviposição e também de gerar prole nos mesmos. Porém, os hospedeiros que receberam a primeira postura das vespas com 0, 24 e 48 de idade tiveram o maior tamanho de prole. Houve diferença no tamanho da prole para as 3ª lagartas parasitadas de 24 e 48 horas de idade enquanto as vespas de 0 h parasitaram, mas não geraram prole no hospedeiro D. saccharalis. Mas, quando comparou-se estatisticamente o a média das três idades o tamanho da prole foi igual. A razão sexual tambémfoi estatisticamente igual em todas idades e nas três posturas. Concluí-se que C. flavipes de 0, 24 e 48 horas de idade são igualmente eficientes no parasitismo de Diatraea saccharalis. / Cotesia flavipes is an endoparasitoid wasp introduced in Brazil to biologically control the host Diatraea saccharalis, commonly known as the sugar cane drill. These insects have been reared for more than thirty years in Brazil, in massal rearing creation laboratories. In times of good female productivity in massal rearing creation laboratories, the parasitoids are used immediately after emergence. Though, in certain periods of the year, insect production presents a sex ratio towards males, so the insects are used after 24 hours in order to guarantee copulation. The objective of this work was to compare the efficiency of C. flavipes of three ages (0, 24 and 48h) in the parasitism of 5th instar D. saccharalis with a density of three hosts. Three hosts were offered to a female parasitoid so that she would deposit eggs in a short time interval with a fixed density. The study verified that C. flavipes of all three ages was capable of parasitizing the three hosts offered for oviposition and also of generating offspring from them. Though, the host which received the wasps first deposit with 0, 24 and 48h of age, had the largest number of offspring. There was a difference in the number of offspring for the third parasitized caterpillar for wasps? aged 24 and 48 h, while newly emerged (0h) wasps parasitized the host D. saccharalis without generating offspring. Although, when the means for the three ages were compared statistically, offspring sizes were equal. Sexual bias was also statistically equal in all three ages and in the three deposits. We conclude that C. flavipes aged 0, 24 and 48 h are equally efficient in the parasitism of D. saccharalis.
17

Produção e razão sexual de Cotesia flavipes (Hymenoptera: Braconidae) em lagartas de Diatraea saccharalis (Lepidoptera: Pyralidae) com diferentes temperaturas e alimentação / Production and sexual ratio of Cotesia flavipes (Hymenoptera: Braconidae) in caterpillars of Diatraea saccharalis (Lepidoptera: Pyralidae) with different temperature and feeding.

Maria Tereza de Morais Henriques 24 September 2007 (has links)
lt;p align="justify"gt; O controle biológico utiliza inimigos naturais para reduzir infestação de pragas. A Cotesia flavipes (Hymenoptera: Braconidae) é uma vespa parasitóide que combate Diatraea saccharalis (Lepidoptera: Pyralidae), praga que causa grandes perdas na produção de cana-de-açúcar (Saccharum officinarum L.). Analisou-se o efeito da temperatura sobre razão sexual do parasitóide C. flavipes em lagartas D. saccharalis. Inoculou-se lagartas com 14 dias de eclosão em temperaturas 21, 25, 30 e 40oC e fotoperíodo de 12 horas. Na temperatura de 25oC foi analisado o efeito da quantidade de alimento sobre as massas secas de machos e fêmeas de C. flavipes e a proporção sexual de C. flavipes sendo realizado um ensaio com quantidades crescentes de alimento (1,0; 1,5; 2,0; 2,5 e 3,0g) para lagarta D. saccharalis inoculada com o parasitóide C. flavipes. Para verificar a razão sexual entre machos e fêmeas de C. flavipes do insetário, 50 massas contendo casulos da vespa C. flavipes foram retiradas aleatoriamente de cinco lotes de diferentes inoculadores, contendo cada placa de Petri quatro lagartas parasitadas. Após a emergência e morte dos adultos de C. flavipes foi contada a quantidade de machos e de fêmeas. Os resultados obtidos mostraram que em relação à temperatura foi observado que a 30 e 40oC ocorreu 100% de mortalidade de D. saccharalis parasitadas. Na temperatura de 21 ± 0,9oC a razão sexual observada foi de 3:5 (machos: fêmeas) enquanto a 25 ± 1,2oC a foi de 2:5 (machos: fêmeas). A quantidade de dieta não apresentou relação com a massa seca total de C. flavipes não afetando, portanto, a proporção sexual. A razão sexual nas condições atuais de criação do parasitóide no insetário observada foi de 3:5 (macho: fêmea).lt;/pgt; / lt;p align="justify"gt; The biological control using natural enemies to reduce the pest infestation. The Cotesia flavipes (Hymenoptera: Braconidae) is a wasp that parasitoid fight Diatraea saccharalis (Lepidoptera: Pyralidae), pest that causes major losses in the production of sugar cane (Saccharum officinarum L.). Examined is the effect of temperature on sex ratio of the parasitoid Cotesia flavipes on caterpillars Diatraea saccharalis. Was inoculated with caterpillars hatch in 14 days of temperatures 21, 25, 30 and 40oC and photoperiod for 12 hours. At temperatures of 25°C was examined the effect of the quantity of food on the masses droughts of males and females of C. flavipes and the proportion of sexual C. flavipes being conducted a test with increasing amounts of food (1.0; 1.5; 2.0; 2.5 and 3.0 g) for caterpillar D. saccharalis inoculated with the parasitoid C. flavipes. To check the sex ratio between males and females of C. flavipes of insetário, 50 bodies containing the wasp cocoons C. flavipes were drawn randomly from five lots of different inoculadores, and each card Petri four inoculated caterpillars. After the emergence and death of adults of C. flavipes was counted the number of males and females. The results showed that in relation to temperature was observed that the 30 and 40oC was 100% mortality of D. saccharalis inoculated. The temperature of 21 ± 0.9°C the observed sex ratio was 3:5 (male: female) while 25 ± 1.2°C was the 2:5 (male: female). The amount of diet not submitted relationship with the total dry weight of C. flavipes not changing, so the proportion sexual. The sex ratio in the current conditions for the creation of parasitoid in insetário observed was 3:5 (male: female).lt;/pgt;
18

Interaction entre la teigne du chou Plutella xylostella (L.) et ses principaux parasitoïdes en conditions tropicales : approche éthologique, écologique et évolutive / Non communiqué

Arvanitakis, Laurence 19 December 2013 (has links)
L'espèce Plutella xylostella (L.) (Lepidoptera : Plutellidae) défoliatrice des choux constitue surtout un problème dans les régions tropicales et subtropicales. La lutte chimique a rapidement montré ses limites du fait de l'apparition de résistance dans les populations. Des moyens de lutte alternatifs ont été mis en place, impliquant principalement des insectes parasitoïdes, parmi lesquels Oomyzus sokolowskii (Kurdjumov) (Hymenoptera : Eulophidae) et Cotesia vestalis (Haliday) (Hymenoptera : Braconidae) qui sont les plus couramment utilisés en raison de leur spécificité envers P. xylostella. Afin de contribuer à une meilleure connaissance du contrôle de la teigne en région tropicale, nous avons étudié les relations hôteparasitoïde entre P. xylostella et O. sokolowskii d’une part, et P. xylostella et C. vestalis d’autre part, en conditions de laboratoire et sur le terrain au Sénégal et au Bénin. Au Sénégal, quatre espèces de parasitoïdes sont présentes sur les chenilles : O. sokolowskii, Apanteles litae, C. vestalis et Brachymeria citrae. Au Bénin, seule l'espèce C. vestalis est présente. Au Sénégal comme au Bénin, les facteurs climatiques contribuent au développement de la teigne et les précipitations ne régulent pas les populations du ravageur. Dans ces deux pays, la teigne n’est pas contrôlée par ses ennemis naturels. La lutte biologique par conservation y est à prendre en considération et l’utilisation de plantes compagnes cultivées en association avec le chou peut être envisagée pour réduire les populations de la teigne. Les études en laboratoire ont montré qu’Oomyzus sokolowskii est un parasitoïde larvo-nymphal performant. ConcernantC. vestalis, les femelles détectent et reconnaissent leur hôte grâce aux lipides cuticulaires émis par les chenilles. Des marqueurs moléculaires (isozymes et ISSR) ont confirmé une forte variabilité entre les populations de P. xylostella à l’échelle mondiale, les populations d’Australie et du Japon étant très différentes des autres et formant deux groupes distincts. La structuration des populations semble influencée par le type de climat : tropical et non tropical. / The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most destructive pest of Brassicaceae worldwide and poses particularly acute problems in tropical areas. Chemical control is impaired by multiple-insecticide resistance in this species. Alternative methods are based on biological control by parasitoids, such as Oomyzussokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) and Cotesia vestalis (Haliday) (Hymenoptera: Braconidae), which are commonly used due to their specificity towards DBM. To help to improve the biocontrol of the moth in the tropics, we studied host-parasitoid relationships between P. xylostella and these two parasitoids under both laboratory and field conditions in Senegal and Benin. In both countries, climatic conditions are favourable for the development of DBM and rainfall does not limit populations of this pest. In Senegal, four parasitoid species are present on DBM larvae: O. sokolowskii, C. vestalis, Apanteles litae, and Brachymeria citrae. In Benin, C. vestalis is largely dominant. In neither of these countries, the moth is sufficiently controlled by natural enemies. Conservation biological control might be combined with the use of companion plants in cabbage crops to reduce DBM populations. Laboratory studies have shown that O. sokolowskii is an efficient larval-pupal parasitoid. In C. vestalis, females detect and recognize their host using cuticular lipids produced by the caterpillar. Studies of molecular markers (isozymes and ISSR) have confirmed high variability among DBM populations around the world, those from Australia and Japan being distinct and very different from any other population. Population structure seems to be influenced by the type of climate (tropical vs. non-tropical).
19

Estratégias de parasitismo da vespa parasitóide Cotesia flavipes, Cameron, 1891 (Hymenoptera:Braconidae) / Comparison between three ages of the parasitoid Cotesia flavipes in the parasitism of Diatraea saccharalis

Marcia Terumi Uehara 26 August 2005 (has links)
Cotesia flavipes é uma vespa endoparasitóide introduzida no Brasil para controlar biologicamente o hospedeiro Diatraea saccharalis, conhecida como a broca da cana-de-açúcar. Estes insetos são criados há mais de trinta anos no Brasil em laboratórios de criação massal. Em épocas de boa produtividade de fêmeas nos laboratórios de criação massal os parasitóides são utilizados logo após a emergência. Porém, em alguns períodos do ano, a produção de insetos apresenta com a razão sexual desviada para machos então, os insetos são utilizados após 24 horas, para tentar garantir a cópula. O objetivo deste trabalho foi comparar a eficiência de C.flavipes de três idades (0, 24 e 48h) no parasitismo de D. saccharalis de 5° instar e com a densidade de 3 hospedeiros. Três hospedeiros foram oferecidos à fêmea parasitóide para que a mesma realizasse as posturas em um curto intervalo de tempo e com densidade fixa. Verificou-se que C. flavipes das três idades foram capazes de parasitar os 3 hospedeiros oferecidos para oviposição e também de gerar prole nos mesmos. Porém, os hospedeiros que receberam a primeira postura das vespas com 0, 24 e 48 de idade tiveram o maior tamanho de prole. Houve diferença no tamanho da prole para as 3ª lagartas parasitadas de 24 e 48 horas de idade enquanto as vespas de 0 h parasitaram, mas não geraram prole no hospedeiro D. saccharalis. Mas, quando comparou-se estatisticamente o a média das três idades o tamanho da prole foi igual. A razão sexual tambémfoi estatisticamente igual em todas idades e nas três posturas. Concluí-se que C. flavipes de 0, 24 e 48 horas de idade são igualmente eficientes no parasitismo de Diatraea saccharalis. / Cotesia flavipes is an endoparasitoid wasp introduced in Brazil to biologically control the host Diatraea saccharalis, commonly known as the sugar cane drill. These insects have been reared for more than thirty years in Brazil, in massal rearing creation laboratories. In times of good female productivity in massal rearing creation laboratories, the parasitoids are used immediately after emergence. Though, in certain periods of the year, insect production presents a sex ratio towards males, so the insects are used after 24 hours in order to guarantee copulation. The objective of this work was to compare the efficiency of C. flavipes of three ages (0, 24 and 48h) in the parasitism of 5th instar D. saccharalis with a density of three hosts. Three hosts were offered to a female parasitoid so that she would deposit eggs in a short time interval with a fixed density. The study verified that C. flavipes of all three ages was capable of parasitizing the three hosts offered for oviposition and also of generating offspring from them. Though, the host which received the wasps first deposit with 0, 24 and 48h of age, had the largest number of offspring. There was a difference in the number of offspring for the third parasitized caterpillar for wasps? aged 24 and 48 h, while newly emerged (0h) wasps parasitized the host D. saccharalis without generating offspring. Although, when the means for the three ages were compared statistically, offspring sizes were equal. Sexual bias was also statistically equal in all three ages and in the three deposits. We conclude that C. flavipes aged 0, 24 and 48 h are equally efficient in the parasitism of D. saccharalis.
20

Impact moléculaire et physiologique de la guêpe parasitoïde Cotesia congregata et de son polydnavirus sur l'insecte hôte Manduca sexta / Molecular and physiological impact of the parasitoid wasp Cotesia congregata and its polydnavirus on the insect host Manduca sexta

Chevignon, Germain 09 December 2014 (has links)
Cotesia congregata est une guêpe parasitoïde qui se développe à l’intérieur de la larve du Lépidoptère, Manduca sexta. Ce parasitoïde a développé une stratégie de virulence qui utilise un symbionte viral de la famille des Polydnavirus nommé Cotesia congregata bracovirus. Mon travail de thèse a permis de caractériser le dialogue moléculaire au cours de l’interaction par des approches de transcriptomique à haut débit et de physiologie. Ces travaux ont permis d’établir la première carte fonctionnelle du génome viral et de visualiser l’ensemble des gènes de M. sexta régulés au cours du parasitisme. La régulation des gènes de l’immunité a révélé que le parasitisme n’empêche pas l’induction de peptides antimicrobiens, mais entraine la sous-expression de gènes impliqués dans la réponse cellulaire. De plus j’ai pu mettre en évidence une réduction du nombre de cellules adhérentes au cours de l’interaction et décrire l’induction d’un phénotype de type apoptose d’une catégorie de cellules immunitaires. Ces résultats permettent d’identifier des gènes acteurs de l’interaction et apportent de nouvelles connaissances relatives aux interactions hôtes-parasitoïdes. / Cotesia congregata is a parasitoid wasp that develops inside the lepidopteran larvae, Manduca sexta. This parasitoid wasp has evolved virulence strategies using an obligate viral symbiont from the Polydnavirus family named Cotesia congregata bracovirus. My thesis work has allowed us to characterize the molecular dialogue during the interaction by physiological and high-throughput transcriptomic approaches. This work allowed to obtain the first functional map of the viral genome and to identify all M. sexta genes regulated during parasitism. Regulation of immune genes revealed that parasitism does not prevent induction of antimicrobial peptides, but leads to the down-regulation of genes involved in the cellular response. Moreover, I was able to demonstrate a reduction in the number of adherent cells during the interaction and to describe this induction as an apoptosis-like phenotype targeting a specific population of immune cells. These findings open the way to the identification of candidate genes involved in this particular interaction and provide new insights into host-parasitoid interactions in general.

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