RESUMEN
Green lacewings are insects with great potential to be use in the biological control of agricultural pests, but relatively few studies have attempted to understand the genetic structure of these agents, especially those of predatory insects. The purpose of this study was to characterize genetically populations of C. externa using sequences of subunit I of the cytochrome oxidase, a mitochondrial gene, and examine the population structure of this species in sampled areas in São Paulo state. The results indicate high genetic diversity but no genetic structure, detected by AMOVA analysis, and high levels of haplotype sharing in the network. These genetic patterns could be a consequence of environmental homogeneity provided by agroecosystem (citrus orchard), allowing gene flow among populations. Probably there is a unique population in the area sampled that could be used as a population (genetic) source for mass-reared and posterior release in these farms.
Asunto(s)
Variación Genética , Insectos/genética , Control Biológico de Vectores , Animales , Complejo IV de Transporte de Electrones/genética , Haplotipos , Proteínas de Insectos/genética , Proteínas Mitocondriales , Análisis de Secuencia de ADNRESUMEN
Abstract Green lacewings are insects with great potential to be use in the biological control of agricultural pests, but relatively few studies have attempted to understand the genetic structure of these agents, especially those of predatory insects. The purpose of this study was to characterize genetically populations of C. externa using sequences of subunit I of the cytochrome oxidase, a mitochondrial gene, and examine the population structure of this species in sampled areas in São Paulo state. The results indicate high genetic diversity but no genetic structure, detected by AMOVA analysis, and high levels of haplotype sharing in the network. These genetic patterns could be a consequence of environmental homogeneity provided by agroecosystem (citrus orchard), allowing gene flow among populations. Probably there is a unique population in the area sampled that could be used as a population (genetic) source for mass-reared and posterior release in these farms.
Resumo Crisopídeos são insetos com grande potencial para uso em controle biológico de pragas agrícolas, mas relativamente poucos estudos têm tentado compreender a estrutura genética destes agentes, especialmente no caso de insetos predadores. O objetivo deste trabalho foi caracterizar geneticamente populações de C. externa utilizando sequências da subunidade I do gene mitocondrial citocromo oxidase e avaliar a estruturação populacional desta espécie em áreas amostras no estado de São Paulo. Os resultados indicaram elevada diversidade genética e nenhuma estruturação genética, detectada pela AMOVA, além de elevado compartilhamento na rede haplotípica. Este padrão genético poderia ser uma consequência da homogeneidade ambiental favorecida pelos agroecossistemas (citricultura), permitindo fluxo gênico entre as populações. Provavelmente há uma única população, do ponto de vista genético, na área amostrada que poderia ser utilizada em criações massais e em liberações nas fazendas desta região.
Asunto(s)
Animales , Variación Genética , Insectos/genética , Control Biológico de Vectores , Complejo IV de Transporte de Electrones/genética , Haplotipos , Proteínas de Insectos/genética , Proteínas Mitocondriales , Análisis de Secuencia de ADNRESUMEN
Four species of green lacewings occur in Brazil, of which Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) exhibits the widest geographical distribution. Chrysoperla externa is a predatory insect that is potentially useful as a biological control agent of agricultural pests. Studies on the genetic diversity of lacewing populations are essential to reduce the environmental and economic harm that may be caused by organisms with a low ability to adapt to the adverse and/or different environmental conditions to which they are exposed. We used the cytochrome oxidase I mitochondrial gene as a molecular marker to investigate the genetic diversity of green lacewing species collected from native and agroecosystem environments. Populations derived from native areas showed higher rates of genetic variability compared to populations from agroecosystems. Demographic changes in the form of population expansion were observed in agroecosystems, whereas populations in the native environment appeared stable over time. A statistical analysis showed significant genetic structure between each of the sampled groups, combined with its complete absence within each group, corroborating each group's identity. We infer that the loss of variability exhibited by populations from the agroecosystems is the result of genetic drift by means of the founder effect, a similar effect that has been observed in other introduced populations. Agroecosystems might therefore function as exotic areas for green lacewings, even when these areas are within the normal range of the species.