Molecular Entomology, 2025, Vol.16, No.1, 11-18 http://emtoscipublisher.com/index.php/me 11 Methodological Paper Open Access Artificial Rearing Methods and Observations of Spodoptera litura on Soybean Plants PingZhu College of Life Science, Hainan Normal University, Haikou, 571158, Hainan, China Corresponding email: ping.zhu@126.com Molecular Entomology, 2025, Vol.16, No.1 doi: 10.5376/me.2025.16.0002 Received: 12 Dec., 2024 Accepted: 15 Jan., 2025 Published: 26 Jan., 2025 Copyright © 2025 Zhu, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Zhu P., 2025, Artificial rearing methods and observations of Spodoptera litura on soybean plants, Molecular Entomology, 16(1): 11-18 (doi: 10.5376/me.2025.16.0002) Abstract Under controlled artificial conditions, the growth cycle and behavioral characteristics of Spodoptera litura (striped stem borer) were observed with soybean plants as the sole feed. Experimental conditions: temperature around 25°C, relative humidity 23%, with a 12-hour light and 12-hour dark alternating cycle. It was observed that the duration from the pupal stage to the next generation pupation was about 45 days, with adult emergence taking about 15 days, mating and oviposition lasting about 2 days, egg hatching taking about 4 days, and the larval stage lasting 22 days, with the prepupal period lasting about 2 days. During the larval rearing process, providing sufficient space and food can reduce cannibalistic behaviors. Observing the reproductive organs of the pupae accurately distinguishes their sex. In environments with lower humidity, reproductive efficiency decreases, with the number of new individuals being only ten times that of the previous generation. Observing Spodoptera litura in an artificial environment provides basic data for biological research, contributing to green pest control strategies and resource utilization. Keywords Spodoptera litura; Soybean; Natural feed; Rearing; Grow 1 Introduction The striped stem borer (Spodoptera litura) belongs to the order Lepidoptera and the family Noctuidae, also known as the lotus-patterned noctuid or the striped noctuid (Islam et al., 2020). Unlike the incompletely metamorphosed dragonflies, Spodoptera litura undergoes complete metamorphosis, like butterflies and mosquitoes, with four distinct developmental stages: egg, larva, pupa, and adult (Zhong et al., 2024). It is a global agricultural pest, widely distributed in China, from Gansu in the west to coastal provinces and Taiwan in the east, from Liaoning in the north to Hainan Island in the south, where the pest has been recorded (Bragard et al., 2019). Data show that Spodoptera litura intermittently erupts in the northern Huai River region, while in the southern Huai River region, especially south of the Yangtze River, it occurs year-round, with increasing damage as one moves further south (Zhang et al., 2023). Hainan Island, due to its unique tropical climate, experiences this pest year-round (Baoqia, 2015). From the perspective of generation, the Spodoptera litura occurs 4~5 generations per year in the Northeast and North China regions; The number of generations in East and Central China has increased to 5~7 (Zhang et al., 2023). Zhang et al. (2014) found that Spodoptera litura occurs 5~6 generations per year in Zhejiang Province, and its active period lasts from late April to early November; In Licheng District, Putian City, Fujian Province, the annual occurrence of Spodoptera litura can reach 6~9 generations, with overlapping generations, and the peak period is concentrated from May to October (Chen, 2010). According to a survey conducted by Qin et al. (2006), the host plants of the Spodoptera litura include 389 species (including varieties) from 109 families, including ferns (such as ferns, wood thieves, apples, etc.), gymnosperms (such as Chinese fir, cypress, ginkgo, etc.), monocotyledonous plants (such as chives, corn, banana, etc.), dicotyledonous plants (the most harmful), leguminous plants (such as soybeans and cowpeas), cruciferous plants (such as cabbage and Chinese cabbage), and other important economic crops (such as cotton and sweet potato). The Spodoptera litura mainly causes harm by feeding on plants as larvae, and has the following characteristics: (1) Gluttony: high-density populations can gnaw on the entire crop leaf in a short period of time, leaving only leaf
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