Avaliação da capacidade de renovação do epitélio do mesêntero e seus efeitos no potencial reprodutivo de fêmeas adultas de Ceraeochrysa claveri (Neuroptera: Chrysopidae) alimentadas durante a fase larval com óleo de nim (azadirachta indica A. JUSS)
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Data
2016-02-24
Autores
Scudeler, Elton Luiz [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Devido ao uso indiscriminado de inseticidas de largo espectro na produção agrícola e a vulnerabilidade dos inimigos naturais a este tipo de exposição, efeitos colaterais podem afetar a função biológica destes inimigos, tornando sua utilização no controle biológico impraticáveis. A busca por pesticidas mais seletivos sobre esses organismos benéficos é necessária, e entre as alternativas, enfatizamos o aumento do uso dos biopesticidas. Um dos biopesticidas amplamente utilizados é o óleo de nim (Azadirachta indica), e sua segurança e compatibilidade com os inimigos naturais têm sido mais esclarecidos através de estudos ecotoxicológicos que verificam os efeitos da exposição indireta através da ingestão de presas contaminadas. Assim, este estudo analisou a resposta das células epiteliais do mesêntero de adultos do crisopídeo Ceraeochrysa claveri quando expostos por ingestão de presa contaminada com óleo de nim durante a fase larval e a ocorrência de efeitos letais e subletais em seu desenvolvimento. Larvas de C. claveri foram alimentadas com ovos de Diatraea saccharalis tratados com óleo de nim nas concentrações de 0,5%, 1% e 2% durante todo período larval. Fêmeas adultas obtidas a partir destes tratamentos foram utilizadas em análises morfológicas e ultraestruturais da resposta celular do mesêntero. Além disso, parâmetros biológicos também foram avaliados durante o desenvolvimento pós-embrionário. O óleo de nim provoca efeitos citotóxicos no mesêntero através de pronunciadas alterações, como dilatação celular, perda da integridade do córtex celular, cisternas dilatadas do retículo endoplasmático rugoso, mitocôndrias inchadas, Complexo de Golgi com aparência vesiculada e invaginações dilatadas no labirinto basal. As células epiteliais responderam a essas lesões por diferentes mecanismos citoprotetores e de detoxificação tais como proliferação celular, aumento de grânulos citoplasmáticos contendo cálcio, expressão da HSP 70, processos autofágicos e desenvolvimento de retículo endoplasmático liso, mas eles não foram suficientes para recuperar todos os danos celulares. Da mesma forma, destacamos a baixa sobrevivência das fêmeas no período de pré-oviposição, e significativos efeitos na reprodução os quais ocasionaram redução da fecundidade, fertilidade e viabilidade de ovos para todas as doses avaliadas. Estes efeitos evidenciam a ausência de compatibilidade, impedindo um sucesso no controle biológico ao tentar integrar este predador com o uso do óleo de nim.
Due to the indiscriminate use of broad-spectrum insecticides in agricultural production and the vulnerability of natural enemies to this type of pesticide exposure, side effects can affect the biological function of these enemies, making their use for biological control unfeasible. A search for more selective pesticides on these beneficial organisms is necessary, and among the alternatives, we emphasize the increased use of biopesticides. One of the biopesticides widely used is the neem oil (Azadirachta indica), and its safety and compatibility with natural enemies have been more clarified through ecotoxicological studies which check the effects of indirect exposure by intake of poisoned preys. Thus, this study analyzed the response of midgut epithelial cells of adult of lacewing Ceraeochrysa claveri when exposed by intake of contaminated prey with neem oil during the larval stage and the occurrence of lethal and sublethal effects on its development. Larvae of C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% throughout the larval stage. Adults female obtained from these treatments were used in the morphological and ultrastructural analyses of cellular response of midgut. Moreover, biological parameters were also measured during the post embryonic development. Neem oil causes cytotoxic effects on the midgut through pronounced alterations as cell swollen, loss of integrity of cell cortex, dilated cisternae of the rough endoplasmic reticulum, swollen mitochondria, Golgi complex with vesiculated appearance and dilated invagination of basal labyrinth. Epithelial cells responded to these injuries by different cytoprotective and detoxification mechanisms such as cell proliferation, increase of cytoplasmatic granules containing calcium, expression of HSP 70, autophagic processes and development of smooth endoplasmic reticulum, but they were not enough to recover all the cellular damages. Likewise, we highlighted the low survival of females in the preoviposition period and the significant effects on reproduction for which a reduction occurred in fecundity, fertility and egg viability for all evaluated doses. These effects show the absence of compatibility, preventing a success in the biological control when trying to integrate this predator with the use of the neem oil.
Due to the indiscriminate use of broad-spectrum insecticides in agricultural production and the vulnerability of natural enemies to this type of pesticide exposure, side effects can affect the biological function of these enemies, making their use for biological control unfeasible. A search for more selective pesticides on these beneficial organisms is necessary, and among the alternatives, we emphasize the increased use of biopesticides. One of the biopesticides widely used is the neem oil (Azadirachta indica), and its safety and compatibility with natural enemies have been more clarified through ecotoxicological studies which check the effects of indirect exposure by intake of poisoned preys. Thus, this study analyzed the response of midgut epithelial cells of adult of lacewing Ceraeochrysa claveri when exposed by intake of contaminated prey with neem oil during the larval stage and the occurrence of lethal and sublethal effects on its development. Larvae of C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% throughout the larval stage. Adults female obtained from these treatments were used in the morphological and ultrastructural analyses of cellular response of midgut. Moreover, biological parameters were also measured during the post embryonic development. Neem oil causes cytotoxic effects on the midgut through pronounced alterations as cell swollen, loss of integrity of cell cortex, dilated cisternae of the rough endoplasmic reticulum, swollen mitochondria, Golgi complex with vesiculated appearance and dilated invagination of basal labyrinth. Epithelial cells responded to these injuries by different cytoprotective and detoxification mechanisms such as cell proliferation, increase of cytoplasmatic granules containing calcium, expression of HSP 70, autophagic processes and development of smooth endoplasmic reticulum, but they were not enough to recover all the cellular damages. Likewise, we highlighted the low survival of females in the preoviposition period and the significant effects on reproduction for which a reduction occurred in fecundity, fertility and egg viability for all evaluated doses. These effects show the absence of compatibility, preventing a success in the biological control when trying to integrate this predator with the use of the neem oil.
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Palavras-chave
Biopesticida, Crisopídeo, Predador, Toxicidade, Ultraestrutura, Biopesticide, Lacewing, Predator, Toxicity, Ultrastructure