Aspectos da ecologia da movimentação e da reprodução como bases para o manejo de spodoptera frugiperda (j. E. Smith) (lepidoptera: noctuidae)
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Data
2022-04-01
Autores
Rezende, Gabriel Fernandes
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Universidade Estadual Paulista (Unesp)
Resumo
A lagarta-do-cartucho do milho, Spodoptera frugiperda, é uma das principais pragas de cultivos agrícolas no mundo. O manejo desse inseto consta de técnicas que, para assegurar sua eficiência a longo prazo, necessitam de conhecimentos básicos a respeito da movimentação e reprodução. Para plantas que expressam proteínas inseticidas, o manejo de pragas deve incluir a adoção de áreas de refúgio próximas das plantas transgênicas para permitir fluxo gênico entre insetos suscetíveis e resistentes. A distância máxima entre o cultivo transgênico e o refúgio leva em consideração o movimento e status sexual dos insetos, os quais não complemente compreendidos. O objetivo desse trabalho foi determinar métodos para se compreender a movimentação de adultos de S. frugiperda, bem como caracterizar o status sexual dos adultos e sua implicação na reprodução. O fornecimento de corantes hidrossolúveis à fase larval não foi efetivo para marcar os espermatóforos transferidos às fêmeas, embora tenha sido eficiente para a marcação de larvas. O estudo da movimentação em campo de milho demonstrou a chegada de adultos de S. frugiperda logo após a emergência de plantas de milho e início da oviposição que deu origem à primeira população desenvolvida na área. Ressalta-se que os primeiros adultos coletados na área incluíram um grande número de fêmeas acasaladas, mas nenhum inseto foi capturado quando as plantas entraram em estágio reprodutivo. No teste de voo tutorado, a capacidade de voo de S. frugiperda não foi afetada pelo status sexual dos adultos. Entretanto, a presença de feromônio aumentou o tempo de voo dos machos. O status sexual dos machos pode ser determinado diretamente por meio da dissecação ou indiretamente pela observação do espermatóforo transmitido à fêmea, embora esse fator não interfira na fertilidade de fêmeas acasaladas com machos previamente virgens ou acasalados. Esse estudo conclui que a presença de feromônio liberado por fêmeas desenvolvidas em área de refúgio apresentam potencial de atração aos machos potencialmente resistentes desenvolvidos em área Bt. Este estudo traz conhecimentos relacionados ao movimento e reprodução da lagarta-do-cartucho e pode ser útil para aprimorar os programas de manejo integrado de pragas e de resistência de insetos.
The fall armyworm, Spodoptera frugiperda, is an important pest of agricultural crops worldwide. The management of this insect pest consists of some techniques whose long-term efficiency needs to be based upon basic knowledge about movement and reproduction. For insecticidal protein-expressing plants, pest management should include the adoption of refuge areas near to the transgenic plants to allow gene flow between susceptible and resistant insects. The maximum distance between the transgenic crop and its associated refuge area takes into consideration the movement and sexual status of insects which are not fully comprehended yet. The objective of this work was to determine methods to understand adult movement of S. frugiperda as well as to characterize the sexual status of adults and its implication in the reproduction. The supply of water-soluble dyes along with larval diet was not effective to mark the spermatophores transferred to females, although it was efficient for marking the larvae. The study of movement in a maize field showed the arrival of adults of S. frugiperda soon after the emergence of plants and onset of oviposition that gave rise to the first in-maize population developed. Interestingly, the first adults caught in the area included a large number of mated females, but no insects were captured when the plants entered the reproductive stage. During the tethered flight tests, the flight ability of S. frugiperda was not affected by the sexual status of adults. However, the presence of pheromone increased the flight time of males. The sexual status of males can be determined directly through dissection or indirectly by observing the spermatophore transferred to the female, although this factor does not affect the fertility of females mated with previously virgin or mated males. This study concludes that the presence of pheromone released by females developed in a refuge area has the potential to attract potentially resistant males developed in a Bt area. This study brings insights related to movement and reproduction of fall armyworm and can be useful to enhance both integrated pest management and insect resistance management programs.
The fall armyworm, Spodoptera frugiperda, is an important pest of agricultural crops worldwide. The management of this insect pest consists of some techniques whose long-term efficiency needs to be based upon basic knowledge about movement and reproduction. For insecticidal protein-expressing plants, pest management should include the adoption of refuge areas near to the transgenic plants to allow gene flow between susceptible and resistant insects. The maximum distance between the transgenic crop and its associated refuge area takes into consideration the movement and sexual status of insects which are not fully comprehended yet. The objective of this work was to determine methods to understand adult movement of S. frugiperda as well as to characterize the sexual status of adults and its implication in the reproduction. The supply of water-soluble dyes along with larval diet was not effective to mark the spermatophores transferred to females, although it was efficient for marking the larvae. The study of movement in a maize field showed the arrival of adults of S. frugiperda soon after the emergence of plants and onset of oviposition that gave rise to the first in-maize population developed. Interestingly, the first adults caught in the area included a large number of mated females, but no insects were captured when the plants entered the reproductive stage. During the tethered flight tests, the flight ability of S. frugiperda was not affected by the sexual status of adults. However, the presence of pheromone increased the flight time of males. The sexual status of males can be determined directly through dissection or indirectly by observing the spermatophore transferred to the female, although this factor does not affect the fertility of females mated with previously virgin or mated males. This study concludes that the presence of pheromone released by females developed in a refuge area has the potential to attract potentially resistant males developed in a Bt area. This study brings insights related to movement and reproduction of fall armyworm and can be useful to enhance both integrated pest management and insect resistance management programs.
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Palavras-chave
Dispersão, Status sexual, Voo tutorado, Plantas hospedeiras, Pragas controle