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

Summary

The protocol demonstrates a simple and easy dissection method, suitable for wild-type migratory female insects captured with searchlight traps. This technique can significantly clarify the same species by comparing both reproductive tissues, namely the mating sac and ovarian development of wild-type female insects.

Abstract

Migratory insect pests pose serious challenges to food production and security all over the world. The migratory pests can be monitored and captured using searchlight traps. One of the most important techniques for migratory pest forecasting is to identify the migratory species. However, in most cases, it is difficult to get the information just by appearance. Therefore, using knowledge acquired by systematic analysis of the female reproductive system can help to understand the combined anatomic morphology of the ovarian mating sac and ovary developmental grading of wild-type migratory insects captured with searchlight traps. To demonstrate the applicability of this method, ovarian development status and egg grain development stages were directly assessed in Helicoverpa armigera, Mythimna separata, Spodoptera litura, and Spodoptera exigua for the ovarian anatomy, and the ovarian mating sacs were studied in Agrotis ipsilon, Spaelotis valida, Helicoverpa armigera, Athetis lepigone, Mythimna separata, Spodoptera litura, Mamestra brassicae, and Spodoptera exigua, to explore their relationships. This work shows the specific dissection method to predict wild-type migratory insects, comparing the unique reproductive system of different migratory insects. Then, both tissues, namely, the ovary and mating sacs, were further investigated. This method helps to predict the dynamics and the structural development of reproductive systems in wild-type female migratory insects.

Introduction

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 China^1,2,3,4. The long travel distances, seasonal movements, high fecundity of migratory pests, and ecological factors have brought great difficulties in the prediction, forecast, and contr....

Protocol

NOTE: Pay attention to safety measurements before trapping wild-type migratory insects, it is suggested to wear safety gear (gloves, long-sleeved shirts, and goggles). Also, turn off the trap when not in use to avoid other safety hazards and overheating the light. It is important to follow safety protocols before dissection, such as wearing gloves, goggles, and lab coat to prevent exposure to body fluids and chemicals.

1. Trapping of migrant insects

1. Begin this prot.......

Discussion

Ovarian analysis methods are routinely used in plant protection, to elucidate the movement of insect flight and population for forecasting^19,20,21 and to elaborate on the physiological variations in insects. It has been noticed that the unique migration and rapid dispersion ability of common agricultural pests, such as bollworm, armyworm, taro caterpillar, and beet moth, make it difficult for prediction from other regions. .......

Materials

Name	Company	Catalog Number	Comments
Digital camera	Canon ( China ) co., LTD	EOS 800D
Dropper	Qingdao jindian biochemical equipment co., LTD
Ethanol absolute (99.7%)	Shanghai Hushi Laboratory Equipmentco., LTD
Forceps	Vetus Tools co., LTD	ST-14
GT75 type halogen headlamp (1000 W)	Shanghai Yadeng Industry co., LTD
Helicoverpa armigera, Mythimna separate, Spodoptera litura, Spodoptera exigua	Jiyang district, Jinan city, Shandong province, China
Measuring cylinder, beaker, flask	Qingdao jindian biochemical equipment co., LTD
Net bag	Qingdao jindian biochemical equipment co., LTD		0.5 m
Net cages	Qingdao jindian biochemical equipment co., LTD		30 cm x 30 cm
Petri dishes	Qingdao jindian biochemical equipment co., LTD		60 mm diameter