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Fagundes, Giovanna Garcia - One of the best experts on this subject based on the ideXlab platform.

  • Estudos Sobre os efeitos de um produto a base de Bacillus Thuringiensis var. Kurstaki em Ephestia Kuehniella (Zeller, 1879) (Lepidoptera: Pyralidade) e no seu Ectoparasitoide Bracon Hebetor (Say, 1836) (Hymenoptera: Braconidae)
    [s.n.], 2018
    Co-Authors: Fagundes, Giovanna Garcia
    Abstract:

    Orientador: Mohamed E. M. HabibTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Ephestia kuhniella é uma expressiva praga de moinhos de trigo. Seu controle é feito basicamente através de produtos químicos sintéticos. Porém, devido aos inúmeros problemas causados ao ambiente e à saúde humana por estas substâncias, novas alternativas para o manejo deste lepidóptero vêm sendo buscadas. Neste sentido, pesquisas em controle biológico, físico e mecânico, entre outros, são fundamentais para embasar novos programas de manejo integrado (MIP) desta praga. Dentre os agentes de controle biológico, produtos à base do entomopatógeno Bacillus thuringiensis var. kurstaki (Btk) e o ectoparasitóide Bracon Hebetor são considerados altamente eficientes no controle de E. kuehniella.Todavia, a inserção destes dois em programas de MIP depende de estudos sobre suas interações na regulação da densidade do piralídeo. Sendo assim, este trabalho propõe avaliar o impacto e as interações dos dois agentes de mortalidade sobre este piralídeo. Para tal buscou-se avaliar a susceptibilidade de larvas de E. kuehniella ao Btk; analisar os efeitos crônicos de Btk no desenvolvimento dos piralídeos sobreviventes; avaliar o impacto da patogenia causada pelo Btk nas larvas de E. kuehniella sobre o desenvolvimento do parasitóide; analisar possíveis interações de compatibilidade, antagonismo ou sinergismo entre o parasitóide e o entomopatógeno e avaliar a capacidade de B. Hebetor de distinguir entre larvas sadias e infectadas por Btk. Os estudos foram realizados no Laboratório de Entomologia Aplicada, do Departamento de Zoologia da UNICAMP, sob condições controladas (25 ± 20 C; 70 ± 10 % de umidade relativa e 12 horas de fotofase). Com os critérios adotados, observou-se que a susceptibilidade de E. kuehniella variou inversamente em função do estádio de desenvolvimento larval. Desta forma, larvas de primeiro estádio apresentaram maior susceptibilidade ao produto à base do patógeno (CL50 = 0,05%; IC = 0,04 % ¿ 0,06 %), seguidas pelas larvas de terceiro, que apresentaram um nível intermediário (CL50 = 0,16%; IC = 0,12 % ¿ 0,20 %). Já as larvas de quinto estádio foram as menos susceptíveis ao Btk (CL50 = 1,77%; IC = 1,42 % ¿ 2,23 %). Os estudos de efeitos agudos e crônicos do patógeno sobre o desenvolvimento, reprodução e longevidade de E. kuehniella elucidaram o caráter variável da resposta biológica ao tratamento em função da idade larval, da concentração do Btk e do tempo de exposição. Larvas de primeiro (L1) e de quinto estádios apresentaram reduções na viabilidade dos estágios imaturos. Adultos xix oriundos de larvas de primeiro e terceiro estádios sobreviventes a tratamento com Btk não apresentaram efeitos crônicos em termos de capacidade reprodutiva e longevidade. Porém, os adultos que se originaram de indivíduos tratados no quinto estádio larval apresentaram menor capacidade reprodutiva. Já a viabilidade dos seus ovos não diferiu do grupo testemunha. A longevidade do piralídeo foi diminuída quando estes adultos foram expostos ao contato direto com o produto microbiano. Este efeito indireto provavelmente foi decorrente do estresse provocado pelo odor do produto. O Btk também foi indiretamente responsável pela redução na capacidade de B. Hebetor paralisar e parasitar larvas de E. kuehniella. Adultos do Braconídeo rejeitaram larvas hospedeiras que manifestavam sintomas da bacteriose. A redução da viabilidade dos imaturos do Braconídeo variou em função da concentração e do tempo de exposição ao tratamento. Todavia, a longevidade dos adultos obtidos desta F1 não foi alterada. O inseticida microbiano também provocou efeitos indiretos sobre a longevidade dos adultos do Braconídeo decorrentes do odor/ contato, com este. A ingestão de mel contendo Btk também diminuiu significativamente a longevidade do ectoparasitóide. Através dos estudos de escolha e olfatometria, pode-se constatar que a localização do hospedeiro por B. Hebetor não é alterada em função da infecção por Btk. Mas, a aceitação das larvas para o parasitismo variou inversamente à concentração do patógeno e ao tempo de tratamento do hospedeiro. Desta forma, a maior rejeição ocorreu nos lotes onde havia a maior proporção de larvas doentes e manifestando sintomas evidentes da patogenia. Em condições laboratoriais, a ação do patógeno, nas concentrações aqui avaliadas, associada ao parasitóide, para o controle de E. kuehniella, apresentou a mesma eficiência que o parasitóide isoladamente. Sendo assim, pode-se concluir que Btk e B. Hebetor atuam de maneira complementar no controle de populações dessa traça, dependendo de quem a atinge primeiro. Se o programa de MIP visa trabalhar com introduções alternadas desses dois agentes biológicos visando controle de larvas em diferentes estádios, haveria uma vantajosa compatibilidade entre estes, que permite a não utilização de produtos químicos, evita a seleção de resistência pelo Btk na população alvo e contorna o problema gerado pelo número de partículas de insetos presentes em produtos para consumo humano, como as farinhas, decorrente da introdução contínua de parasitóidesAbstract: Ephestia kuehniella is a very important pest, attacking wheat flour in mills and stored places. Due to the negative impact of the chemical control methods, alternative agents are being studied to reach more safety and more satisfactory results. Some biological, physical and mechanical components should be adequate to be includes in integrated pest management programs (IPM) to reduce the injury of this lepidopterous pest. Within the biological agents, Bacillus thuringiensis var. kurstaki (Btk) and the Braconid wasp Bracon Hebetor are considered very efficient in controlling, separately, E. kuehniella populations. However, the insertion of these two agents in IPM programs needs some studies concerning the interaction between them and their natural pyralid host. The present study aimed to investigate the interaction between Btk and B. Hebetor, in addition to evaluate their efficiency in controlling E. kuehniella. Within such a purpose some approaches were studied, such as: susceptibility of E. kuehniella larvae to Btk; chronic effects of Btk on the survived individuals; effect of diseased and survived E. kuehniella larvae on B. Hebetor development; compatibility between the two biological agents and B. Hebetor capacity to distinguish between healthy and diseased hosts. All experiments were conducted under controlled laboratory conditions of 25 ± 20C, 70 ± 10% R. H. and 12 hours of photophase (Department of Zoology, IB, UNICAMP). The pyralid larval susceptibility varied according to the age. The young larvae (L1) showed to be more susceptible than the old ones (L3 and L5). The CL50s were calculated as 0,05%; 0,16% and 1,77% for the first, third and fifth instars respectively. The acute as well as the chronic effects of Btk on E. kuehniella development varied according to the exposure time, age and pathogen concentration. Adults originated from survived E. kuehniella larvae did not show any biological or structural alterations, when the pathogen was applied against the first and thirdinstar larvae. On the other hand, adults originated from survived 5th instar larvae suffered reduction in their reproductive capacity. The egg viability in all these cases did not reveal any significant differences when compared with testimony block. The direct contact of Btk commercial product resulted in reduced longevity among E. kuehniella adults. Reduction in longevity was also detected when B. Hebetor females were kept in contact with the same product. The Braconid female parasite was able to distinguish between healthy and diseased host larvae, avoiding to attack the later. Parasitization capacity was reduced when the wasp female was able to deposit its eggs in pyralid larvae during the initial phase of the bacterial disease. B. Hebetor adult longevity was reduced when parasitoid wasps were fed on honey containing Btk. Combinations between the two biological agents did not result in any synergistic effect under the conditions of the present study, and both of then could be recommended to be applied in wheat millsDoutoradoParasitologiaDoutor em Ciências Biológica

  • Analise do efeito da radiação de microondas sobre Anagasta Kuhniella Zeller (1879) (Lepidoptera: Pyralidae) e seus dois agentes de controle biologico, Bracon hebertor (Say, 1836) (Hymenoptera: Braconidae) e Bacillus thuringiensis var. kurstaki (H:3a3b)
    [s.n.], 2018
    Co-Authors: Fagundes, Giovanna Garcia
    Abstract:

    Orientador: Mohamed HabibDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O conceito de Manejo Integrado de Pragas (MIP) busca a utilização consciente de métodos de controle ambientalmente seguros e economicamente viáveis. Neste contexto, é de extrema importância o conhecimento das interações entre os agentes de controle a serem empregados, para garantir maior eficiência na implantação de tais programas. Tanto as microondas (300 a 300.000 MHz), como o Bacillus thuringiensis varo kurstaki e o ectoparasitóide Bracon Hebetor (Say, 1836) vêm sendo estudados isoladamente como promissores agentes de controle de pragas em produtos armazenados. Este trabalho teve por objetivo analisar as respostas e relações do parasitóide Bracon Hebetor, do seu hospedeiro natural, o piralídeo Anagasta kühniella Zeller (1879) e do entomopatógeno, B. thuringiensis varo kurstaki (Sorotipo H­3a:3b) à radiação de Microondas (2.450 MHz). o material entomológico foi coletado em moinho de farinha em Campinas, SP, e utilizado para dar início a criações laboratoriais . As condições adotadas neste trabalho foram de 25 ::!: 2 o C, 60 ::!: 10 % de umidade relativa (UR) e 12 horas de fotoperíodo. Para os biensaios de avaliação da sensibilidade de Bacillus thuringiensis varo Iwrstaki a microondas foram utilizadas amostras do produto Dipel (Abbot @), contendo o complexo esporo - cristal desta bactéria, 16.000 UII mg de virulência, formulação em pó molhável. Todos os bioensaios, envolvendo a utilização de radiação, foram realizados sob a potência máxima de um forno microondas Panasonic NN 7954 8H I K, operando na freqüência de 2.450 MHz. Tanto o piralídeo, como como o parasitóide, apresentaram uma relação positiva entre o aumento do tempo de exposição e a mortalidade, independentemente do estágio de vida avaliado. No caso de esporos de B. thur;ng;ens;s irradiados, esta relação foi visualizada no bioensaio realizado na concentração de 0,2%, a qual é próxima à CLso das larvas de terceiro estádio. Quanto à sensibilidade das diferentes fases de desenvolvimento de Anagasta kühn;ella à microondas observou-se a existência de um gradiente de sensibilidade entre os estágios de desenvolvimento do piralídeo : larvas de último estádio (TELso = 15,63 s) > larvas de terceiro estádio (TELso = 19,34 s) > adultos (TELso = 22,61 s) > ovos (TELso = 121,67 s), provavelmente decorrente de diferenças físico- químicas. Encontrou-se diferenças significativas quanto ao impacto de microondas nos diferentes estágios de desenvolvimento dos ovos de Anagasta kühn;ella (1 e 4 dias de idade) quando usado tempos de exposição subletais (10 e 30 segundos). Os ovos de 4 dias demonstraram ser mais sensíveis à radiação que os de 1 dia de idade. Já no caso das exposições letais (45, 60 e 90 segundos) não houve indício de diferenças nas duas etapas de desenvolvimento embrionário. As larvas que eclodiram dos ovos tratados com radiação não portavam nenhum tipo de alteração morfológica. Quanto à interferência do meio no impacto causado em larvas de último estádio por exposição à radiação não se constatou diferença significativa entre as larvas expostas diretamente (TELso = 15,63 s) e em meio de farinha de trigo integral (TELso = 16,28 s). A sintomatologia apresentada após o tratamento com radiação variou em função do tempo de exposição. Observou-se desde letargia, desfunção do sistema locomotor até dessecamento, escurecimento do tegumento e morte. A análise da influência da radiação na capacidade reprodutiva e na longevidade de adultos do piralídeo sobreviventes à exposição indicou que as microondas provocam alterações negativas em ambos os casos. Entretanto, a radiação não influiu na viabilidade dos ovos colocados pelas fêmeas tratadas. Os adultos de Bracon Hebetor demonstraram um nível de tolerância à radiação de microondas bem maior (TELso = 106,57 s) que as larvas (TELso = 15,63 s) e adultos (TELso = 22,61 s) do seu piralídeo hospedeiro, Anagasta kühniella, enquanto as larvas do Braconídeo (TELso = 20,31 s) aparentemente apresentam o mesmo nível de sensibilidade do píralídeo praga. A exposição do produto à base de Bacillus thuringiensis varo kurstaki à radiação de microondas, nas concentrações letais (2,6%) e sub-Ietais (0,02%) não influiu no seu potencial patogênico. Entretanto, na concentração próxima à letal mediana (CLso) observou-se que o aumento do tempo de exposição à radiação diminuiu a patogenicidade da bactéria. Sendo assim, a radiação de microondas apresentou-se como um método de controle bastante promissor para Anagasta kühniella criada em farinha de trigo integral. Pode ser empregado em ecossistemas de armazemagem deste produto em associação ao ectoparasitóide Bracon Hebetor e ao Bacillus thuringiensis varo kurstakiAbstract: The application of Integrated Pest Management (IPM) means the utilization of efficient control methods which are ecologically safe and economicaly viable. Therefore, it is extremaly important to gather more information about the possible interactions between the different control agents, aimimg to optimize such a method. Microwaves (300 a 300.000 MHz), as well as Bacillus thuringiensis and the ectoparasitoid Bracon Hebetor (Say, 1836) are being studied individually by some institutions, as promissing control agents of some stored product pests. The present work was developed to study and evaluate the relations among the parasite Bracon Hebetor, his natural host, Anagasta kühniella Zeller (1879), the entomopathogen Bacillus thuringiensis' varo kurstaki (H- 3a:3b) and microwaves radiation. The mother culture of the pyralid and Braconid species were initiated from live material collected from flour mills in Campinas municipality, state of São Paulo. The cultures were maintained and experiments were realized under controlled laboratory condítions of 25 :t 2° C, 60 :t 10 % R.H. and 12 hours of photoperiod. To evaluate the tolerance of B. thuringiensis to microwave radiation samples of the commercial product Dipel (Abbot) were utilized. This product contains 16,000 IUI mg and formulated as a wettable powder. The radiation treatments were undertaken utilizing the maximum potency of a domestic Panasonic microwave oven (NN 7954 BH/K, 2450 MHz). The mortality rate among the different developmental stages of the two insect species was observed to be positively related with the radiation exposure time. Among the Anagasta kühniella developmental stages, while the last instar larvae showed to be more sensitive to radiation (median letal exposure time, LET 50 = 15,63 s), the egg stage showed to be more resistant (LETso= 121,67 s). The third instar larvae, as well the adult stage, revealed a moderate sensitivity (LETso= 19,34 s and 22,61 s, respectively). Within the egg stage of Anagasta kühniella the full grow embryo showed to be more sensitive than newly deposited eggs. The impact of the direct exposition to microwaves on the full grow Anagasta kühniella larvae (LET so= 15,63 s) did not differ when compared with those larvae imbeded in their natural diet, whole wheat flour (LETso = 16,28 s). The sequence and intensity of the external symptoms, showed to be directly related to the duration time in which larvae of Anagasta kühniella were exposed to the microwave radiation. Letargy and locomotion desfunctions were the initial alterations. Dehydration and body wall darkening , reaching dark brown, were observed before death. The radiation also showed to be harmful to the adult stage of the same pyralidae species, reducing longevity as well as reproductive capacity. Bracon Hebetor adults showed to be more resistant to radiation (LETso ::: 106,57 s) when compared to Anagasta kühniella adults (LETso = 22,61 s) and larvae (LET50 = 15,63 s). Samples of Bacillus thuringiensis var kurstaki were exposed to different times of microwaves radiation (2450 MHz) and were ofered to third instar larvae of Anagasta kühniella in three different concentrations (0.02 %, 0.2% and 2.6%). This electromagnetic wave did not present any interference in the patogenicity of the entomopathogen in the extrem concentrations (0.02 and 2.6%). However, in the 0.2% concentration, next to LCso of the larvae, the patogenicity of Bacillus thuringiensis was altered by the time of exposure to the radiation. Finally, radiation by microwaves could be considered as a promissing method, efficient and compatible with biological control ones, to participate in IPM programs of the Mediterranean Flour Moth, Anagasta kühniellaMestradoParasitologiaMestre em Ciências Biológica

Giovanna Garcia Fagundes - One of the best experts on this subject based on the ideXlab platform.

  • Estudos Sobre os efeitos de um produto a base de Bacillus Thuringiensis var. Kurstaki em Ephestia Kuehniella (Zeller, 1879) (Lepidoptera: Pyralidade) e no seu Ectoparasitoide Bracon Hebetor (Say, 1836) (Hymenoptera: Braconidae)
    Universidade Estadual de Campinas. Instituto de Biologia, 2004
    Co-Authors: Giovanna Garcia Fagundes
    Abstract:

    Ephestia kuhniella é uma expressiva praga de moinhos de trigo. Seu controle é feito basicamente através de produtos químicos sintéticos. Porém, devido aos inúmeros problemas causados ao ambiente e à saúde humana por estas substâncias, novas alternativas para o manejo deste lepidóptero vêm sendo buscadas. Neste sentido, pesquisas em controle biológico, físico e mecânico, entre outros, são fundamentais para embasar novos programas de manejo integrado (MIP) desta praga. Dentre os agentes de controle biológico, produtos à base do entomopatógeno Bacillus thuringiensis var. kurstaki (Btk) e o ectoparasitóide Bracon Hebetor são considerados altamente eficientes no controle de E. kuehniella.Todavia, a inserção destes dois em programas de MIP depende de estudos sobre suas interações na regulação da densidade do piralídeo. Sendo assim, este trabalho propõe avaliar o impacto e as interações dos dois agentes de mortalidade sobre este piralídeo. Para tal buscou-se avaliar a susceptibilidade de larvas de E. kuehniella ao Btk; analisar os efeitos crônicos de Btk no desenvolvimento dos piralídeos sobreviventes; avaliar o impacto da patogenia causada pelo Btk nas larvas de E. kuehniella sobre o desenvolvimento do parasitóide; analisar possíveis interações de compatibilidade, antagonismo ou sinergismo entre o parasitóide e o entomopatógeno e avaliar a capacidade de B. Hebetor de distinguir entre larvas sadias e infectadas por Btk. Os estudos foram realizados no Laboratório de Entomologia Aplicada, do Departamento de Zoologia da UNICAMP, sob condições controladas (25 ± 20 C; 70 ± 10 % de umidade relativa e 12 horas de fotofase). Com os critérios adotados, observou-se que a susceptibilidade de E. kuehniella variou inversamente em função do estádio de desenvolvimento larval. Desta forma, larvas de primeiro estádio apresentaram maior susceptibilidade ao produto à base do patógeno (CL50 = 0,05%; IC = 0,04 % ? 0,06 %), seguidas pelas larvas de terceiro, que apresentaram um nível intermediário (CL50 = 0,16%; IC = 0,12 % ? 0,20 %). Já as larvas de quinto estádio foram as menos susceptíveis ao Btk (CL50 = 1,77%; IC = 1,42 % ? 2,23 %). Os estudos de efeitos agudos e crônicos do patógeno sobre o desenvolvimento, reprodução e longevidade de E. kuehniella elucidaram o caráter variável da resposta biológica ao tratamento em função da idade larval, da concentração do Btk e do tempo de exposição. Larvas de primeiro (L1) e de quinto estádios apresentaram reduções na viabilidade dos estágios imaturos. Adultos xix oriundos de larvas de primeiro e terceiro estádios sobreviventes a tratamento com Btk não apresentaram efeitos crônicos em termos de capacidade reprodutiva e longevidade. Porém, os adultos que se originaram de indivíduos tratados no quinto estádio larval apresentaram menor capacidade reprodutiva. Já a viabilidade dos seus ovos não diferiu do grupo testemunha. A longevidade do piralídeo foi diminuída quando estes adultos foram expostos ao contato direto com o produto microbiano. Este efeito indireto provavelmente foi decorrente do estresse provocado pelo odor do produto. O Btk também foi indiretamente responsável pela redução na capacidade de B. Hebetor paralisar e parasitar larvas de E. kuehniella. Adultos do Braconídeo rejeitaram larvas hospedeiras que manifestavam sintomas da bacteriose. A redução da viabilidade dos imaturos do Braconídeo variou em função da concentração e do tempo de exposição ao tratamento. Todavia, a longevidade dos adultos obtidos desta F1 não foi alterada. O inseticida microbiano também provocou efeitos indiretos sobre a longevidade dos adultos do Braconídeo decorrentes do odor/ contato, com este. A ingestão de mel contendo Btk também diminuiu significativamente a longevidade do ectoparasitóide. Através dos estudos de escolha e olfatometria, pode-se constatar que a localização do hospedeiro por B. Hebetor não é alterada em função da infecção por Btk. Mas, a aceitação das larvas para o parasitismo variou inversamente à concentração do patógeno e ao tempo de tratamento do hospedeiro. Desta forma, a maior rejeição ocorreu nos lotes onde havia a maior proporção de larvas doentes e manifestando sintomas evidentes da patogenia. Em condições laboratoriais, a ação do patógeno, nas concentrações aqui avaliadas, associada ao parasitóide, para o controle de E. kuehniella, apresentou a mesma eficiência que o parasitóide isoladamente. Sendo assim, pode-se concluir que Btk e B. Hebetor atuam de maneira complementar no controle de populações dessa traça, dependendo de quem a atinge primeiro. Se o programa de MIP visa trabalhar com introduções alternadas desses dois agentes biológicos visando controle de larvas em diferentes estádios, haveria uma vantajosa compatibilidade entre estes, que permite a não utilização de produtos químicos, evita a seleção de resistência pelo Btk na população alvo e contorna o problema gerado pelo número de partículas de insetos presentes em produtos para consumo humano, como as farinhas, decorrente da introdução contínua de parasitóides.Ephestia kuehniella is a very important pest, attacking wheat flour in mills and stored places. Due to the negative impact of the chemical control methods, alternative agents are being studied to reach more safety and more satisfactory results. Some biological, physical and mechanical components should be adequate to be includes in integrated pest management programs (IPM) to reduce the injury of this lepidopterous pest. Within the biological agents, Bacillus thuringiensis var. kurstaki (Btk) and the Braconid wasp Bracon Hebetor are considered very efficient in controlling, separately, E. kuehniella populations. However, the insertion of these two agents in IPM programs needs some studies concerning the interaction between them and their natural pyralid host. The present study aimed to investigate the interaction between Btk and B. Hebetor, in addition to evaluate their efficiency in controlling E. kuehniella. Within such a purpose some approaches were studied, such as: susceptibility of E. kuehniella larvae to Btk; chronic effects of Btk on the survived individuals; effect of diseased and survived E. kuehniella larvae on B. Hebetor development; compatibility between the two biological agents and B. Hebetor capacity to distinguish between healthy and diseased hosts. All experiments were conducted under controlled laboratory conditions of 25 ± 20C, 70 ± 10% R. H. and 12 hours of photophase (Department of Zoology, IB, UNICAMP). The pyralid larval susceptibility varied according to the age. The young larvae (L1) showed to be more susceptible than the old ones (L3 and L5). The CL50s were calculated as 0,05%; 0,16% and 1,77% for the first, third and fifth instars respectively. The acute as well as the chronic effects of Btk on E. kuehniella development varied according to the exposure time, age and pathogen concentration. Adults originated from survived E. kuehniella larvae did not show any biological or structural alterations, when the pathogen was applied against the first and thirdinstar larvae. On the other hand, adults originated from survived 5th instar larvae suffered reduction in their reproductive capacity. The egg viability in all these cases did not reveal any significant differences when compared with testimony block. The direct contact of Btk commercial product resulted in reduced longevity among E. kuehniella adults. Reduction in longevity was also detected when B. Hebetor females were kept in contact with the same product. The Braconid female parasite was able to distinguish between healthy and diseased host larvae, avoiding to attack the later. Parasitization capacity was reduced when the wasp female was able to deposit its eggs in pyralid larvae during the initial phase of the bacterial disease. B. Hebetor adult longevity was reduced when parasitoid wasps were fed on honey containing Btk. Combinations between the two biological agents did not result in any synergistic effect under the conditions of the present study, and both of then could be recommended to be applied in wheat mill

  • Analise do efeito da radiação de microondas sobre Anagasta Kuhniella Zeller (1879) (Lepidoptera: Pyralidae) e seus dois agentes de controle biologico, Bracon hebertor (Say, 1836) (Hymenoptera: Braconidae) e Bacillus thuringiensis var. kurstaki (H:3a3b)
    Universidade Estadual de Campinas. Instituto de Biologia, 1998
    Co-Authors: Giovanna Garcia Fagundes
    Abstract:

    O conceito de Manejo Integrado de Pragas (MIP) busca a utilização consciente de métodos de controle ambientalmente seguros e economicamente viáveis. Neste contexto, é de extrema importância o conhecimento das interações entre os agentes de controle a serem empregados, para garantir maior eficiência na implantação de tais programas. Tanto as microondas (300 a 300.000 MHz), como o Bacillus thuringiensis varo kurstaki e o ectoparasitóide Bracon Hebetor (Say, 1836) vêm sendo estudados isoladamente como promissores agentes de controle de pragas em produtos armazenados. Este trabalho teve por objetivo analisar as respostas e relações do parasitóide Bracon Hebetor, do seu hospedeiro natural, o piralídeo Anagasta kühniella Zeller (1879) e do entomopatógeno, B. thuringiensis varo kurstaki (Sorotipo H­3a:3b) à radiação de Microondas (2.450 MHz). o material entomológico foi coletado em moinho de farinha em Campinas, SP, e utilizado para dar início a criações laboratoriais . As condições adotadas neste trabalho foram de 25 ::!: 2 o C, 60 ::!: 10 % de umidade relativa (UR) e 12 horas de fotoperíodo. Para os biensaios de avaliação da sensibilidade de Bacillus thuringiensis varo Iwrstaki a microondas foram utilizadas amostras do produto Dipel (Abbot @), contendo o complexo esporo - cristal desta bactéria, 16.000 UII mg de virulência, formulação em pó molhável. Todos os bioensaios, envolvendo a utilização de radiação, foram realizados sob a potência máxima de um forno microondas Panasonic NN 7954 8H I K, operando na freqüência de 2.450 MHz. Tanto o piralídeo, como como o parasitóide, apresentaram uma relação positiva entre o aumento do tempo de exposição e a mortalidade, independentemente do estágio de vida avaliado. No caso de esporos de B. thur;ng;ens;s irradiados, esta relação foi visualizada no bioensaio realizado na concentração de 0,2%, a qual é próxima à CLso das larvas de terceiro estádio. Quanto à sensibilidade das diferentes fases de desenvolvimento de Anagasta kühn;ella à microondas observou-se a existência de um gradiente de sensibilidade entre os estágios de desenvolvimento do piralídeo : larvas de último estádio (TELso = 15,63 s) > larvas de terceiro estádio (TELso = 19,34 s) > adultos (TELso = 22,61 s) > ovos (TELso = 121,67 s), provavelmente decorrente de diferenças físico- químicas. Encontrou-se diferenças significativas quanto ao impacto de microondas nos diferentes estágios de desenvolvimento dos ovos de Anagasta kühn;ella (1 e 4 dias de idade) quando usado tempos de exposição subletais (10 e 30 segundos). Os ovos de 4 dias demonstraram ser mais sensíveis à radiação que os de 1 dia de idade. Já no caso das exposições letais (45, 60 e 90 segundos) não houve indício de diferenças nas duas etapas de desenvolvimento embrionário. As larvas que eclodiram dos ovos tratados com radiação não portavam nenhum tipo de alteração morfológica. Quanto à interferência do meio no impacto causado em larvas de último estádio por exposição à radiação não se constatou diferença significativa entre as larvas expostas diretamente (TELso = 15,63 s) e em meio de farinha de trigo integral (TELso = 16,28 s). A sintomatologia apresentada após o tratamento com radiação variou em função do tempo de exposição. Observou-se desde letargia, desfunção do sistema locomotor até dessecamento, escurecimento do tegumento e morte. A análise da influência da radiação na capacidade reprodutiva e na longevidade de adultos do piralídeo sobreviventes à exposição indicou que as microondas provocam alterações negativas em ambos os casos. Entretanto, a radiação não influiu na viabilidade dos ovos colocados pelas fêmeas tratadas. Os adultos de Bracon Hebetor demonstraram um nível de tolerância à radiação de microondas bem maior (TELso = 106,57 s) que as larvas (TELso = 15,63 s) e adultos (TELso = 22,61 s) do seu piralídeo hospedeiro, Anagasta kühniella, enquanto as larvas do Braconídeo (TELso = 20,31 s) aparentemente apresentam o mesmo nível de sensibilidade do píralídeo praga. A exposição do produto à base de Bacillus thuringiensis varo kurstaki à radiação de microondas, nas concentrações letais (2,6%) e sub-Ietais (0,02%) não influiu no seu potencial patogênico. Entretanto, na concentração próxima à letal mediana (CLso) observou-se que o aumento do tempo de exposição à radiação diminuiu a patogenicidade da bactéria. Sendo assim, a radiação de microondas apresentou-se como um método de controle bastante promissor para Anagasta kühniella criada em farinha de trigo integral. Pode ser empregado em ecossistemas de armazemagem deste produto em associação ao ectoparasitóide Bracon Hebetor e ao Bacillus thuringiensis varo kurstakiThe application of Integrated Pest Management (IPM) means the utilization of efficient control methods which are ecologically safe and economicaly viable. Therefore, it is extremaly important to gather more information about the possible interactions between the different control agents, aimimg to optimize such a method. Microwaves (300 a 300.000 MHz), as well as Bacillus thuringiensis and the ectoparasitoid Bracon Hebetor (Say, 1836) are being studied individually by some institutions, as promissing control agents of some stored product pests. The present work was developed to study and evaluate the relations among the parasite Bracon Hebetor, his natural host, Anagasta kühniella Zeller (1879), the entomopathogen Bacillus thuringiensis' varo kurstaki (H- 3a:3b) and microwaves radiation. The mother culture of the pyralid and Braconid species were initiated from live material collected from flour mills in Campinas municipality, state of São Paulo. The cultures were maintained and experiments were realized under controlled laboratory condítions of 25 :t 2° C, 60 :t 10 % R.H. and 12 hours of photoperiod. To evaluate the tolerance of B. thuringiensis to microwave radiation samples of the commercial product Dipel (Abbot) were utilized. This product contains 16,000 IUI mg and formulated as a wettable powder. The radiation treatments were undertaken utilizing the maximum potency of a domestic Panasonic microwave oven (NN 7954 BH/K, 2450 MHz). The mortality rate among the different developmental stages of the two insect species was observed to be positively related with the radiation exposure time. Among the Anagasta kühniella developmental stages, while the last instar larvae showed to be more sensitive to radiation (median letal exposure time, LET 50 = 15,63 s), the egg stage showed to be more resistant (LETso= 121,67 s). The third instar larvae, as well the adult stage, revealed a moderate sensitivity (LETso= 19,34 s and 22,61 s, respectively). Within the egg stage of Anagasta kühniella the full grow embryo showed to be more sensitive than newly deposited eggs. The impact of the direct exposition to microwaves on the full grow Anagasta kühniella larvae (LET so= 15,63 s) did not differ when compared with those larvae imbeded in their natural diet, whole wheat flour (LETso = 16,28 s). The sequence and intensity of the external symptoms, showed to be directly related to the duration time in which larvae of Anagasta kühniella were exposed to the microwave radiation. Letargy and locomotion desfunctions were the initial alterations. Dehydration and body wall darkening , reaching dark brown, were observed before death. The radiation also showed to be harmful to the adult stage of the same pyralidae species, reducing longevity as well as reproductive capacity. Bracon Hebetor adults showed to be more resistant to radiation (LETso ::: 106,57 s) when compared to Anagasta kühniella adults (LETso = 22,61 s) and larvae (LET50 = 15,63 s). Samples of Bacillus thuringiensis var kurstaki were exposed to different times of microwaves radiation (2450 MHz) and were ofered to third instar larvae of Anagasta kühniella in three different concentrations (0.02 %, 0.2% and 2.6%). This electromagnetic wave did not present any interference in the patogenicity of the entomopathogen in the extrem concentrations (0.02 and 2.6%). However, in the 0.2% concentration, next to LCso of the larvae, the patogenicity of Bacillus thuringiensis was altered by the time of exposure to the radiation. Finally, radiation by microwaves could be considered as a promissing method, efficient and compatible with biological control ones, to participate in IPM programs of the Mediterranean Flour Moth, Anagasta kühniell

Michael F. Antolin - One of the best experts on this subject based on the ideXlab platform.

  • diversity of sex determining alleles in Bracon Hebetor
    Heredity, 1999
    Co-Authors: George E Heimpel, Michael F. Antolin, Michael R Strand
    Abstract:

    In many hymenopterans, sex is determined at a single polymorphic ‘sex locus’. Individuals that are heterozygous at this locus develop as females whereas homozygotes and hemizygotes develop as diploid and haploid males, respectively. Diploid males are developmentally inviable or sterile, and the likelihood of diploid male production depends in large part on allelic diversity at the sex locus. We assessed sex allele diversity within and among five U.S. populations of the parasitoid wasp Bracon Hebetor using a series of crosses between isofemale lines. The study included two laboratory populations originating in Wisconsin, two field populations originating in Kansas and California, and a population purchased from a commercial insectary. Given the number of isofemale lines that we established, the maximum number of alleles that we could detect per population was 10. The number of sex alleles identified within populations ranged between three or four (for the two Wisconsin populations) and nine (for the California population). Subsampling three or four alleles from each population for between-population crosses led to identification of 12 alleles. Of these, four were unique to the California population, three were unique to one other population each, and one was found in only two populations. Extrapolation of the relationships between the subsampled lines led to a total estimate of 20 alleles within our lines. The relatively high allele diversity in the field and commercial insectary populations suggests that the sex determination load is relatively low in B. Hebetor, and the differences in allele profiles between populations suggest that interpopulation dispersal can increase sex allele diversity within populations.

  • Environmental and genetic determinants of ovicide in parasitic wasp Bracon Hebetor
    Behavioral Ecology, 1997
    Co-Authors: Keiji Takasu, Michael F. Antolin
    Abstract:

    Superparasitism occurs when a parasitoid lays a second dutch of eggs on a host previously parasitized by herself or a conspecific. Ovidde refers to a parasitoid destroying an ^H«ring dutch of eggs on a parasitized host before laying a second clutch. We investigated environmental and genetic determinants of ovidde in the parasitic wasp Bracon Hebetor. Characterization of egglaying behavior revealed that B. Hebetor commits ovidde during the host examination phase of oviposition. The temporal costs of ovidde were found to be relatively small for females that experienced low rates of host encounter, whereas the costs of ovidde increased for females that experienced a high rate of host encounter. Individual wasps committed ovidde on conspecifically parasitized hosts more frequently than on self-parasiti zed hosts. Manipulation experiments suggested that B. Hebetor females learn about their environment while foraging and commit ovidde on die basis of die travel time between successive hosts. Significant differences were also found in oviddal behavior among laboratory and field populations of B. Hebetor. The implications of our results for dutch size theory and die evolution of ovidde are discussed. Key words: Bracon Hebetor, competition, foraging, infantidde, ovidde, parasitoid, reproduction, superparasitism. [Behav Ecol 8:647-654 (1997)] M

  • reproductive isolation and genetic variation between two strains of Bracon Hebetor hymenoptera Braconidae
    Biological Control, 1997
    Co-Authors: George E Heimpel, Michael F. Antolin, Rosa A Franqui, Michael R Strand
    Abstract:

    Abstract Bracon HebetorSay(Hymenoptera: Braconidae) is known primarily as a parasitoid of pyralid moth larvae infesting stored grain. In the 1970s, a parasitoid identified asB. Hebetorwas released for control ofHeliothis/Helicoverpaspp. (Lepidoptera: Noctuidae) on the island of Barbados. Because life-history traits of this parasitoid differed from those reported forB. Hebetorfrom the United States, we conducted a series of laboratory experiments to determine whether this parasitoid was (i) a population ofB. Hebetorthat attacks noctuids in the field or (ii) a different species fromB. Hebetor.We confirmed thatHeliothis virescens(F.) was a more suitable host for the Barbados strain than forB. Hebetor.However, a stored-grain infesting pyralid,Plodia interpunctella(Hubner), was a more suitable host for the Barbados strain than wasH. virescens.Reciprocal crosses between the Barbados strain andB. Hebetorshowed that the two populations were reproductively isolated. No mating was observed during a series of 30-min observations of reciprocal crosses, and the crosses produced only male offspring. Examination of each female's spermatheca confirmed that females were not fertilized. Sequence analysis of a 517-bp fragment of the mitochondrial 16S rRNA gene revealed that two populations ofB. Hebetorfrom our laboratory were identical but differed in sequence by 2% from the Barbados strain. Collectively, our results indicate that the Barbados strain is a distinct species fromB. Hebetor.

  • sex allocation and sexual asymmetries in intra brood competition in the parasitic wasp Bracon Hebetor
    Journal of Animal Ecology, 1996
    Co-Authors: Paul J. Ode, Michael F. Antolin, Michael R Strand
    Abstract:

    1. Bracon Hebetor is a gregarious parasitoid with a female-biased sex ratio. While female-biased sex ratios are often indicative of local mate competition (LMC), B. Hebetor outbreeds, making LMC an unlikely explanation for biased sex ratios in this species. In this study we examined an alternative hypothesis that may explain female-biased sex ratios: competitive asymmetries between larval sons and daughters. 2. We measured two types of competitive asymmetries: asymmetric density responses (differential responses to clutch size), and asymmetric composition responses (responses to change in clutch sex ratio). We measured competitive asymmetries in terms of their effects on body size, development time, survivorship, longevity, and daily and lifetime fecundity or mating ability. 3. Males and females emerged as smaller adults, developed more quickly and experienced higher rates of larval mortality when they developed in larger clutches. The effect of clutch size on body size and survivorship was similar for males and females. Increasing clutch size decreased male larval development time more than female development time, although the effect was marginal. 4. Male and female body sizes increased as within-clutch sex ratios became more male-biased, indicating that females, not males, are stronger competitors. This should lead to male-biased sex ratios, rather than the female-biased sex ratios that exist in B. Hebetor. Sex ratio had no influence on developmental time or survivorship of either sex. 5. Larger males and females lived longer than smaller individuals, whether they fed on hosts or honey. Larger females had higher daily and lifetime fecundities than smaller females. Larger males copulated with more females and sired more daughters both per day and per lifetime than did smaller males. These body size effects were only detectable when hosts were abundant. At low host densities, differences between large and small wasps were absent. 6. Although we detected asymmetric composition responses in terms of body size, the effects were slight. Therefore, we conclude that competitive asymmetries are unlikely to have important effects on male and female fitness or on the sex allocation decisions of B. Hebetor.

  • intensive linkage mapping in a wasp Bracon Hebetor and a mosquito aedes aegypti with single strand conformation polymorphism analysis of random amplified polymorphic dna markers
    Genetics, 1996
    Co-Authors: Michael F. Antolin, Michael R Strand, Christopher F Bosio, Julie L S Cotton, W P Sweeney, William C Black
    Abstract:

    The use of random amplified polymorphic DNA from the polymerase chain reaction (RAPD-PCR) allows efficient construction of saturated linkage maps. However, when analyzed by agarose gel electrophoresis, most RAPD-PCR markers segregate as dominant alleles, reducing the amount of linkage information obtained. We describe the use of single strand conformation polymorphism (SSCP) analysis of RAPD markers to generate linkage maps in a haplodiploid parasitic wasp Bracon (HabroBracon) Hebetor and a diploid mosquito, Aedes aegypti. RAPD-SSCP analysis revealed segregation of codominant alleles at markers that appeared to segregate as dominant (band presence/band absence) markers or appeared invariant on agarose gels. Our SSCP protocol uses silver staining to detect DNA fractionated on large thin polyacrylamide gels and reveals more polymorphic markers than agarose gel electrophoresis. In B. Hebetor, 79 markers were mapped with 12 RAPD primers in six weeks; in A. aegypti, 94 markers were mapped with 10 RAPD primers in five weeks. Forty-five percent of markers segregated as codominant loci in B. Hebetor, while 11% segregated as codominant loci in A. aegypti. SSCP analysis of RAPD-PCR markers offers a rapid and inexpensive means of constructing intensive linkage maps of many species.

Michael R Strand - One of the best experts on this subject based on the ideXlab platform.

  • diversity of sex determining alleles in Bracon Hebetor
    Heredity, 1999
    Co-Authors: George E Heimpel, Michael F. Antolin, Michael R Strand
    Abstract:

    In many hymenopterans, sex is determined at a single polymorphic ‘sex locus’. Individuals that are heterozygous at this locus develop as females whereas homozygotes and hemizygotes develop as diploid and haploid males, respectively. Diploid males are developmentally inviable or sterile, and the likelihood of diploid male production depends in large part on allelic diversity at the sex locus. We assessed sex allele diversity within and among five U.S. populations of the parasitoid wasp Bracon Hebetor using a series of crosses between isofemale lines. The study included two laboratory populations originating in Wisconsin, two field populations originating in Kansas and California, and a population purchased from a commercial insectary. Given the number of isofemale lines that we established, the maximum number of alleles that we could detect per population was 10. The number of sex alleles identified within populations ranged between three or four (for the two Wisconsin populations) and nine (for the California population). Subsampling three or four alleles from each population for between-population crosses led to identification of 12 alleles. Of these, four were unique to the California population, three were unique to one other population each, and one was found in only two populations. Extrapolation of the relationships between the subsampled lines led to a total estimate of 20 alleles within our lines. The relatively high allele diversity in the field and commercial insectary populations suggests that the sex determination load is relatively low in B. Hebetor, and the differences in allele profiles between populations suggest that interpopulation dispersal can increase sex allele diversity within populations.

  • reproductive isolation and genetic variation between two strains of Bracon Hebetor hymenoptera Braconidae
    Biological Control, 1997
    Co-Authors: George E Heimpel, Michael F. Antolin, Rosa A Franqui, Michael R Strand
    Abstract:

    Abstract Bracon HebetorSay(Hymenoptera: Braconidae) is known primarily as a parasitoid of pyralid moth larvae infesting stored grain. In the 1970s, a parasitoid identified asB. Hebetorwas released for control ofHeliothis/Helicoverpaspp. (Lepidoptera: Noctuidae) on the island of Barbados. Because life-history traits of this parasitoid differed from those reported forB. Hebetorfrom the United States, we conducted a series of laboratory experiments to determine whether this parasitoid was (i) a population ofB. Hebetorthat attacks noctuids in the field or (ii) a different species fromB. Hebetor.We confirmed thatHeliothis virescens(F.) was a more suitable host for the Barbados strain than forB. Hebetor.However, a stored-grain infesting pyralid,Plodia interpunctella(Hubner), was a more suitable host for the Barbados strain than wasH. virescens.Reciprocal crosses between the Barbados strain andB. Hebetorshowed that the two populations were reproductively isolated. No mating was observed during a series of 30-min observations of reciprocal crosses, and the crosses produced only male offspring. Examination of each female's spermatheca confirmed that females were not fertilized. Sequence analysis of a 517-bp fragment of the mitochondrial 16S rRNA gene revealed that two populations ofB. Hebetorfrom our laboratory were identical but differed in sequence by 2% from the Barbados strain. Collectively, our results indicate that the Barbados strain is a distinct species fromB. Hebetor.

  • sex allocation and sexual asymmetries in intra brood competition in the parasitic wasp Bracon Hebetor
    Journal of Animal Ecology, 1996
    Co-Authors: Paul J. Ode, Michael F. Antolin, Michael R Strand
    Abstract:

    1. Bracon Hebetor is a gregarious parasitoid with a female-biased sex ratio. While female-biased sex ratios are often indicative of local mate competition (LMC), B. Hebetor outbreeds, making LMC an unlikely explanation for biased sex ratios in this species. In this study we examined an alternative hypothesis that may explain female-biased sex ratios: competitive asymmetries between larval sons and daughters. 2. We measured two types of competitive asymmetries: asymmetric density responses (differential responses to clutch size), and asymmetric composition responses (responses to change in clutch sex ratio). We measured competitive asymmetries in terms of their effects on body size, development time, survivorship, longevity, and daily and lifetime fecundity or mating ability. 3. Males and females emerged as smaller adults, developed more quickly and experienced higher rates of larval mortality when they developed in larger clutches. The effect of clutch size on body size and survivorship was similar for males and females. Increasing clutch size decreased male larval development time more than female development time, although the effect was marginal. 4. Male and female body sizes increased as within-clutch sex ratios became more male-biased, indicating that females, not males, are stronger competitors. This should lead to male-biased sex ratios, rather than the female-biased sex ratios that exist in B. Hebetor. Sex ratio had no influence on developmental time or survivorship of either sex. 5. Larger males and females lived longer than smaller individuals, whether they fed on hosts or honey. Larger females had higher daily and lifetime fecundities than smaller females. Larger males copulated with more females and sired more daughters both per day and per lifetime than did smaller males. These body size effects were only detectable when hosts were abundant. At low host densities, differences between large and small wasps were absent. 6. Although we detected asymmetric composition responses in terms of body size, the effects were slight. Therefore, we conclude that competitive asymmetries are unlikely to have important effects on male and female fitness or on the sex allocation decisions of B. Hebetor.

  • intensive linkage mapping in a wasp Bracon Hebetor and a mosquito aedes aegypti with single strand conformation polymorphism analysis of random amplified polymorphic dna markers
    Genetics, 1996
    Co-Authors: Michael F. Antolin, Michael R Strand, Christopher F Bosio, Julie L S Cotton, W P Sweeney, William C Black
    Abstract:

    The use of random amplified polymorphic DNA from the polymerase chain reaction (RAPD-PCR) allows efficient construction of saturated linkage maps. However, when analyzed by agarose gel electrophoresis, most RAPD-PCR markers segregate as dominant alleles, reducing the amount of linkage information obtained. We describe the use of single strand conformation polymorphism (SSCP) analysis of RAPD markers to generate linkage maps in a haplodiploid parasitic wasp Bracon (HabroBracon) Hebetor and a diploid mosquito, Aedes aegypti. RAPD-SSCP analysis revealed segregation of codominant alleles at markers that appeared to segregate as dominant (band presence/band absence) markers or appeared invariant on agarose gels. Our SSCP protocol uses silver staining to detect DNA fractionated on large thin polyacrylamide gels and reveals more polymorphic markers than agarose gel electrophoresis. In B. Hebetor, 79 markers were mapped with 12 RAPD primers in six weeks; in A. aegypti, 94 markers were mapped with 10 RAPD primers in five weeks. Forty-five percent of markers segregated as codominant loci in B. Hebetor, while 11% segregated as codominant loci in A. aegypti. SSCP analysis of RAPD-PCR markers offers a rapid and inexpensive means of constructing intensive linkage maps of many species.

  • host searching and mating in an outbreeding parasitoid wasp
    Ecological Entomology, 1996
    Co-Authors: D S Guertin, Michael R Strand, Michael F. Antolin
    Abstract:

    . 1 Female parasitoid wasps (Hymenoptera) must search for hosts to reproduce, but only require mates if their broods are to contain female progeny. In outbreeding species, females locate mates after dispersal from the emergence site. Unmated females may therefore face a trade-off between searching for hosts and searching for mates, if hosts and mates are spatially separated. 2 In the outbreeding parasitoid Bracon Hebetor Say (Hymenoptera: Braconidae), males and females are spatially segregated in the field. Females are found primarily below the surface of stored corn where they search for hosts, whereas males are found on or above the surface. 3 Wasps placed in laboratory observation chambers designed to mimic B.Hebetor's stored corn habitat distributed themselves in a manner consistent with field observations. Males remained on the surface of the grain, whereas females moved below the surface to attack hosts. 4 In the laboratory, female distribution was influenced by their mating status, the presence of males or hosts, and female age. Virgin females were more reluctant to move into the corn than were mated females, younger females foraged deeper than older females, and all females moved deeper into the com when males were present. 5 10% of all females did not mate even when males were present in the chambers, a percentage consistent with previous observations from the field. If B.Hebetor faces a trade-off between host-searching and mate-searching, the trade-off seems to be part of 'split sex ratio strategies', with some females remaining constrained to producing only male offspring.

Kemal Buyukguzel - One of the best experts on this subject based on the ideXlab platform.

  • the influence of chronic eicosanoid biosynthesis inhibition on life history of the greater waxmoth galleria mellonella and its ectoparasitoid Bracon Hebetor
    Journal of Insect Physiology, 2011
    Co-Authors: Ender Büyükgüzel, Hasan Tunaz, David Stanley, Kemal Buyukguzel
    Abstract:

    Eicosanoids are oxygenated metabolites of three C20 polyunsaturated fatty acids, mainly arachidonic acid (AA; 20:4n-6), but also 20:3n-6 and 20:5n-3. Aside from their importance in biomedicine, eicosanoids act in invertebrate biology. Prostaglandins (PGs) influence salt and water transport physiology in insect rectal epithelia and in Malpighian tubules. PGs also influence a few insect behaviors, including releasing oviposition behavior and behavioral fever. Eicosanoids act in ovarian development and in insect immunity. Because eicosanoids act in several areas of insect biology, we posed the hypothesis that chronic inhibition of eicosanoid biosynthesis, in the absence of microbial challenge, can influence insect life table parameters, including developmental time, survival, adult longevity and parasitoid fecundity. Here we report that inhibiting eicosanoid biosynthesis throughout the larval life exerted minor influences on some life table parameters of the greater wax moth, Galleria mellonella and its ectoparasitoid, Bracon Hebetor, however, the inhibitors strongly reduced the production and hatchability of the parasitoids' eggs. The significance of the work relates to the potentials of understanding and targeting eicosanoid systems as a platform for developing new technologies of insect pest management. As seen here, the impact of targeting eicosanoid systems is seen in crucial moments of insect life histories, such as reproduction or immune challenge rather than in overall larval development.

  • The influence of chronic eicosanoid biosynthesis inhibition on life history of the greater waxmoth, Galleria mellonella and its ectoparasitoid, Bracon Hebetor
    Journal of Insect Physiology, 2011
    Co-Authors: Ender Büyükgüzel, Hasan Tunaz, David Stanley, Kemal Buyukguzel
    Abstract:

    Eicosanoids are oxygenated metabolites of three C20 polyunsaturated fatty acids, mainly arachidonic acid (AA; 20:4n-6), but also 20:3n-6 and 20:5n-3. Aside from their importance in biomedicine, eicosanoids act in invertebrate biology. Prostaglandins (PGs) influence salt and water transport physiology in insect rectal epithelia and in Malpighian tubules. PGs also influence a few insect behaviors, including releasing oviposition behavior and behavioral fever. Eicosanoids act in ovarian development and in insect immunity. Because eicosanoids act in several areas of insect biology, we posed the hypothesis that chronic inhibition of eicosanoid biosynthesis, in the absence of microbial challenge, can influence insect life table parameters, including developmental time, survival, adult longevity and parasitoid fecundity. Here we report that inhibiting eicosanoid biosynthesis throughout the larval life exerted minor influences on some life table parameters of the greater wax moth, Galleria mellonella and its ectoparasitoid, Bracon Hebetor, however, the inhibitors strongly reduced the production and hatchability of the parasitoids' eggs. The significance of the work relates to the potentials of understanding and targeting eicosanoid systems as a platform for developing new technologies of insect pest management. As seen here, the impact of targeting eicosanoid systems is seen in crucial moments of insect life histories, such as reproduction or immune challenge rather than in overall larval development. © 2011 Elsevier Ltd.