Ren Qilin, Haseeb Muhammad, Fan Jingyu, Wu Pengxiang, Tian Tianqi, Zhang Runzhi
Department of Entomology, Guizhou University, Guizhou 550025, China.
Center for Biological Control, College of Agriculture and Food Sciences, Florida A&M University, Tallahassee, FL 32307-4100, USA.
Insects. 2020 Nov 16;11(11):806. doi: 10.3390/insects11110806.
Functional responses of the fall armyworm (FAW) larvae at each stage, and their intraspecific competition associated with cannibalism, provide insights into developing pest management strategies for the FAW. To help use insecticides more sparingly, the functional response and intraspecific competition of the FAW larvae were evaluated under the laboratory conditions. The results showed that all stages of the FAW larvae displayed a type II functional response to diet. Based on Holling's disc equation, the search rate () and handling time () of sixth instar larvae ( = 0.493; = 0.37 min) were the highest, and the shortest of all larval stages, respectively. Intraspecific competition curves fitted the data for fourth to sixth larval stages of the FAW, and the coefficient of intraspecific competition () assessed by the intraspecific competition equation were highest for fifth instar larvae ( = 0.48). The present study indicates that 5th and 6th instar larvae can cause the most plant damage (accounted for 88.9% of larval consumption), and these stages should be the focus of any pest management strategy. Intraspecific competition, especially cannibalism, impacts the feeding patterns of the FAW larvae and needs close attention. Understanding the functional response and intraspecific competition of the FAW larvae contributes greatly to practical applications of insecticides, increasing the effectiveness of chemical sprays and decreasing ecological damage.
草地贪夜蛾幼虫各阶段的功能反应及其与同类相食相关的种内竞争，为制定草地贪夜蛾害虫管理策略提供了见解。为了更谨慎地使用杀虫剂，在实验室条件下评估了草地贪夜蛾幼虫的功能反应和种内竞争。结果表明，草地贪夜蛾幼虫的所有阶段对食物均表现出II型功能反应。根据霍林圆盘方程，六龄幼虫的搜索率（a = 0.493）和处理时间（Th = 0.37分钟）分别是所有幼虫阶段中最高和最短的。种内竞争曲线拟合了草地贪夜蛾幼虫第四至第六阶段的数据，通过种内竞争方程评估的种内竞争系数（I）在五龄幼虫中最高（I = 0.48）。本研究表明，五龄和六龄幼虫造成的植物损害最大（占幼虫消耗量的88.9%），这些阶段应成为任何害虫管理策略的重点。种内竞争，尤其是同类相食，会影响草地贪夜蛾幼虫的取食模式，需要密切关注。了解草地贪夜蛾幼虫的功能反应和种内竞争对杀虫剂的实际应用有很大帮助，可提高化学喷雾的效果并减少生态破坏。
