Name: Noctuidae Insect Preparation, Dissection, and Ovarian Tissue Analysis
Uploaded: 2023-07-14T14:30:00
Description: Watch this Scientific Journal Video about Noctuidae Insect Preparation, Dissection, and Ovarian Tissue Analysis at JoVE.com

noctuidae insect preparation, dissection, and ovarian tissue analysis

Dissection for Identifying Migratory Insects via Ovarian Reproductive Analysis

Migration of insects plays a vital role in population dynamics of global insect distribution for insects like Helicoverpa armigera - the cotton bollworm, Mythimna separate - the oriental armyworm, Spodoptera litura - the taro caterpillar, Spodoptera exigua - the beet armyworm, that have been reported as serious pests in China1,2,3,4. The long travel distances, seasonal movements, high fecundity of migratory pests, and ecological factors have brought great difficulties in the prediction, forecast, and control of these pests5. Pest migration monitoring is required to reveal the adaptability and behavioral changes that facilitate migratory pests according to climate changes or cycles6. To sustain their growth, reproduction, and survival, insects have acquired sequential adaptability during evolution; this series of adaptive life has generated many changes in the reproductive system, such as migratory strategy leading to control of ovarian development in the long migratory process.
Ovarian development is common in migratory pests, which affects the growth of their population7. Therefore, ovarian development has been a hot topic of migratory pest research for a long time. A series of studies have led to several ovarian development indicators and classification strategies. Until now, several methods have been used to analyze ovary development, e.g., Loxostege sticticalis - the meadow moth- ovary development which includes the initial feathering stage, the early spawning period, the spawning period, and the end of oviposition8. Some researchers divide ovarian levels on the bases of yolk color development in migratory Lepidopteran pests, such as S. exigua - the beet armyworm, Pseudaletia unipuncta - the true armyworm, and Cnaphalocrocis medinalis- the rice leaf-folder, etc.9,10,11,12. In previous studies, the ovarian development levels for pests, such as cotton bollworm and rice leaf roller, were divided into five stages: yolk deposition stage, egg grain maturity stage, mature waiting for birth, peak ovogenesis period, and end spawning stage13,14. The ovarian development of the European corn borer was divided into six developmental stages: yolk deposition stage, egg maturation, pre-eggs dispositioning, peak spawning stage, and end-spawning stage15.
Moreover, insects of the same genus have different stages of development, such as ovarian development levels of Spodoptera frugiperda - the fall armyworm - falls into four levels: yolk deposition stage, mature waiting for delivery, peak ovi-positivity, and end spawning stage16. On the other hand, ovarian development in Spodoptera exigua - the beet moth - has five levels: transparent, vitellogenesis, maturation of eggs, egg release, and late egg-laying levels17.
Former studies can only classify development from single to multiple ovarian development levels using color maturity of yolk, oviposition, and egg developments, but classification cannot be done based on anatomy of the reproductive system. The development of an ovary based on the morphogenesis anatomy is a less studied area. Here, the dissection method was designed to predict migratory females in the population using two ovarian tissue types, to elaborate their reproductive dynamics based on the anatomical morphogenesis of -ovarian development stage and mating sac- providing direct evidence to distinguish migratory wild-type females.
Some studies have found that, migratory Noctuidae insect species were frequently captured by searchlights18. The ovary of most migratory Noctuidae insect species is in the early stages of development during the initial stage of migration and the ovarian level increases with the migratory progress. In this study, the dissection method for ovarian development grades is described, to study the two reproductive tissues of different female population pests, captured by search light. This method not only advances the research to understand the migratory dynamics, but also facilities in insect classification, insect physiology study, pest prediction, and forecasting of female pest species.

Author Spotlight: Analysis of Ovarian Anatomy in Migratory Insects to Overcome Experimental Challenges 

Dissecção e classificação do desenvolvimento ovariano em fêmeas selvagens

We aim to apply easy and this newest method for migratory pest, in describing the ovarian anatomy of migratory females. This information will be useful to analyze similar individual species. To predict migratory female insects is pretty challenging.Therefore, visualization of ovarian anatomy is quite easy and very useful.

Watch this Scientific Journal Video about Noctuidae Insect Preparation, Dissection, and Ovarian Tissue Analysis at JoVE.com

Noctuidae Insect Preparation, Dissection, and Ovarian Tissue Analysis  

Noctuidae Preparo, dissecção e análise do tecido ovariano de insetos

Comece transferindo todos os insetos Noctuidae coletados do saco de rede para uma gaiola de rede. Em seguida, forneça uma placa de Petri contendo uma solução de água de mel esterilizada a 10%. Coloque a gaiola em um ambiente estável.Escolha insetos fêmeas selvagens que se aventuraram dentro da gaiola no mesmo dia. Transfira cuidadosamente esses insetos para tubos de frascos individuais, garantindo que cada tubo seja selado com uma tampa de algodão. Para a dissecção do inseto, primeiro coloque uma fêmea recém-paralisada em uma placa de Petri dissecante contendo etanol absoluto.Para garantir uma dissecação limpa, infiltre o inseto com álcool absoluto e enxágue-o em água limpa. Em seguida, com pinças, separe as asas dorsais na junção do tórax e abdômen. Transfira o abdômen para um novo prato descartável cheio de dois a cinco milímetros de água.Usando pinça dissecante, descasque suavemente o exoesqueleto abdominal, começando da boca pontiaguda dorsoventralmente até a cauda. Replique essas etapas do outro lado e coloque-o em água limpa para dispersar os tecidos intactos. Agora descasque delicadamente os tecidos gordurosos da epiderme usando pinças e puxe e solte suavemente os ovários.Com um par de pinças dissecantes, remova suavemente as partículas de gordura e quaisquer órgãos circundantes dos ovários. Descasque gradualmente o saco de acasalamento do meio e elimine as partículas de gordura ligadas às trompas ovarianas. Segure suavemente o ovário e o saco de acasalamento da extremidade posterior vertical e, em seguida, desdobre-o lentamente para baixo.Para evitar danos, transfira o ovário para uma placa de Petri nova ou limpa cheia de água. Segure a ponta ovariana e desdobre o ovário para dentro. Avaliar a maturidade dos ovos do inseto por meio de indicadores de cor e tamanho.Em seguida, julgue o grau ovariano de acordo com o desenvolvimento do óvulo. Após a dissecção, certifique-se de separar os tecidos do saco de acasalamento feminino dos ovários intactos. Examinar a morfologia como as características anatômicas do saco acasalamento diferem de espécie para espécie.Em seguida, analise a anatomia ovariana dividindo os tecidos ovarianos em cinco graus distintos. Por fim, capture imagens do ovário usando uma câmera digital de acordo com os requisitos do experimento. Quatro diferentes estágios de desenvolvimento ovariano foram observados, incluindo o estágio branco leitoso transparente com ovários subdesenvolvidos, o estágio de deposição de gema com ovos grandes e levemente imaturos, o estágio de amadurecimento com ovos em forma de grânulos amarelos brilhantes e o estágio final de desova com poucos ou nenhum grão de ovo.O saco reprodutivo de um inseto selvagem Helicoverpa armigera tinha uma hélice colunar direita com uma luz interna. Mythimna separata tinha um saco de acasalamento em forma de G com faixas marrons escuras. O saco reprodutivo de Agrotis ipsilon foi linear com grandes bobinas de cistos externos posteriores.Spaelotis valida tinha um saco de acasalamento fino levemente acastanhado em forma de J, enquanto Spodoptera exigua mostrou um saco branco translúcido em forma de haltere com um cisto de bolha no meio. O saco reprodutivo de Spodoptera litura era vermelho, com uma boca branca e leitosa superior transparente e uma cavidade cística interna discretamente visível. O saco reprodutivo de Pseudoptera lepigone era pequeno e enrolado com cistos externos fechados.Mamestra brassicae tinha sacos espirais duplos cor de oliva com cistos externos. A graduação ovariana de vermes antigos mostrou ductos ovarianos transparentes e elásticos com ovócitos visíveis de grau um. No grau dois, o ducto ovariano tornou-se transparente com ovos amarelos tenros.No grau três, grandes corpos gordurosos estavam ausentes, com o ducto mais espesso no ovipositor. Os graus quatro e cinco apresentaram cachos e menos ovos nos ovários com coloração amarelo-pálido e esverdeada. Todos os cinco graus ovarianos também foram observados na lagarta-do-cartucho, na lagarta do tarô e na lagarta-do-cartucho.

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JoVE Journal

Behavior

Noctuidae Insect Preparation, Dissection, and Ovarian Tissue Analysis

Dissection and Grading of Ovarian Development in Wild-Type Female Insects

Migratory insect pests pose serious challenges to food production and security all over the world. The migratory pests can be monitored and captured using ...