Desempenho de populações geográficas de Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) em dietas naturais e artificial e caracterização por microssatélites
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2017-04-12
Autores
Silva, Ivana Fernandes [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) possui ampla distribuição geográfica e é reponsável por perdas econômicas em várias culturas de importância agrícola ao redor do mundo. As lagartas apresentam grande plasticidade em termos de exigência nutricional e, devido à polifagia, se adaptam a diversos hospedeiros, com valores nutricionais variados, os quais podem afetar seu desenvolvimento biológico. Considerando a recente introdução do inseto no Brasil (2013), aliada à falta de consenso sobre a origem das populações a campo, dificuldades no estabelecimento de criações massais, bem como a necessidade de maior entendimento sobre sua interação com os hospedeiros em nosso país, este estudo teve como objetivos: disponibilizar uma dieta padronizada para criações de H. armigera em laboratório (25±2°C, 70±10% U.R. e 14h de fotofase), caracterizar molecularmente três populações, de São Paulo, Bahia e Distrito Federal, avaliar o desempenho biológico e o potencial biótico de indivíduos provenientes de diferentes populações em dieta artificial e investigar a performance de H. armigera em estruturas vegetativas e reprodutivas de algodão, milho e soja. As análises moleculares mostraram similaridade elevada entre indivíduos das três populações, indicando uma origem única para H. armigera no Brasil. O método de criação, bem como os índices nutricionais da dieta artificial oferecida se revelaram adequados para o inseto. A viabilidade média das fases larval e pré-pupal foi semelhante nas três populações. A duração média em dias das pupas fêmeas de seis instares foi de 11,4; 11,6 e 12,0 dias, para as populações de SP, DF e BA, respectivamente. As fêmeas de São Paulo apresentaram a maior média de peso pupal. A progênie proveniente de algodão (BA) apresentou maior potencial biótico, maior taxa reprodutiva e melhor fecundidade em relação aos insetos das outras regiões. Nos tecidos vegetativos e reprodutivos de soja, milho e algodão, os índices de viabilidade larval variaram de 22% a 55%, enquanto que na dieta artificial a viabilidade foi de 62%. Na comparação com as dietas naturais, a dieta artificial se revelou como o substrato mais adequado ao desenvolvimento de H. armigera, no entanto, não se deve descartar a variabilidade na composição nutricional dos hospedeiros naturais a campo, bem como a oferta mista a partir de diferentes partes da planta ou migração entre espécies vegetais durante a fase larval do inseto.
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has a wide geographical distribution and contributes to economic losses in several crops of agricultural importance around the world. The larvae present great plasticity in terms of nutritional requirement and, due to polyphagia, they adapt to several hosts with varied nutritional values which may affect their biological development. Taking into account the recent introduction of these insects in Brazil (2013), along with the lack of consensus on the origin of their populations in the field, as well as the difficulties in establishing mass creations, and the need for greater understanding of their interaction with the hosts in our country, this study had as its objectives: to provide a standardized diet for laboratory H. armigera (25±2°C, 70±10% R.H., and 14h of phototophase); to molecularly characterize three populations from São Paulo (SP), Bahia (BA), and Distrito Federal (DF); to evaluate the biological performance and biotic potential of individuals from different populations on artificial diet; and to investigate the performance of H. armigera in vegetative and reproductive structures of cotton, corn and soybean. The molecular analyzes showed a high similarity between individuals of the three populations, which indicates a unique origin for H. armigera in Brazil. The breeding method, as well as the nutritional indexes of the artificial diet offered, was adequate for the insects. The mean viability of the larval and prepupal stages was similar in all three populations. The mean duration in days of female pupae of six instars was 11.4; 11.6 and 12.0 days for the populations of SP, DF and BA, respectively. Females from São Paulo had the highest mean pupal weight. Progeny from cotton in BA presented higher biotic potential, higher reproductive rate and better fecundity in relation to the insects from the other regions. In the vegetative and reproductive tissues of soybean, corn and cotton, larval viability ranged from 22% to 55%, while in the artificial diet, viability was 62%. In comparison with natural diets, the artificial diet proved to be the most adequate substrate for the development of H. armigera; however, the variability in the nutritional composition of the natural hosts in the field should not be ruled out, neither the mixed supply from different parts of the plant, nor the migration among plant species during the larval stage of the insect.
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has a wide geographical distribution and contributes to economic losses in several crops of agricultural importance around the world. The larvae present great plasticity in terms of nutritional requirement and, due to polyphagia, they adapt to several hosts with varied nutritional values which may affect their biological development. Taking into account the recent introduction of these insects in Brazil (2013), along with the lack of consensus on the origin of their populations in the field, as well as the difficulties in establishing mass creations, and the need for greater understanding of their interaction with the hosts in our country, this study had as its objectives: to provide a standardized diet for laboratory H. armigera (25±2°C, 70±10% R.H., and 14h of phototophase); to molecularly characterize three populations from São Paulo (SP), Bahia (BA), and Distrito Federal (DF); to evaluate the biological performance and biotic potential of individuals from different populations on artificial diet; and to investigate the performance of H. armigera in vegetative and reproductive structures of cotton, corn and soybean. The molecular analyzes showed a high similarity between individuals of the three populations, which indicates a unique origin for H. armigera in Brazil. The breeding method, as well as the nutritional indexes of the artificial diet offered, was adequate for the insects. The mean viability of the larval and prepupal stages was similar in all three populations. The mean duration in days of female pupae of six instars was 11.4; 11.6 and 12.0 days for the populations of SP, DF and BA, respectively. Females from São Paulo had the highest mean pupal weight. Progeny from cotton in BA presented higher biotic potential, higher reproductive rate and better fecundity in relation to the insects from the other regions. In the vegetative and reproductive tissues of soybean, corn and cotton, larval viability ranged from 22% to 55%, while in the artificial diet, viability was 62%. In comparison with natural diets, the artificial diet proved to be the most adequate substrate for the development of H. armigera; however, the variability in the nutritional composition of the natural hosts in the field should not be ruled out, neither the mixed supply from different parts of the plant, nor the migration among plant species during the larval stage of the insect.
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Performance biológica, Populações, Parâmetros nutricionais, Hospedeiros, Dieta artificial