The migratory behaviour of Scotogramma trifolii in the Central Asian insect migration zone
Author of the article:YANG Jing, WANG Shu-Yue, ZHA Xu-Dong, LIU Chen-Cai, ROMAN Jashenko, JI Rong
Author's Workplace：College of Life Science, Xinjiang Normal University, Key Laboratory of Special Species and Regulatory Biology in Xinjiang, International Center for the Collaborative Management of Cross-border Pests in Central Asia, Urumqi 830054, China
Key Words：Scotogramma trifolii; ovarian development; radar observations; meteorological conditions; insect migration zone
Abstract：
[Objectives] To investigate differences between the migration behavior of Scotogramma trifolii in the Central Asian insect migration zone and other migration zones. [Methods] The migratory behavior of S. trifolii in the Tacheng area of Xinjiang was observed for three consecutive years from 2019 to 2021 using insect radar, auxiliary aerial lights and ground lights. During the peak migration period, flight altitude, speed, direction and meteorological characteristics were measured in years in which S. trifolii was abundant. [Results] During the peak migration period, ovarian development was mainly at level 3 or 4, and the male to female ratio was >1. Flight height ranged from 200-1 000 m, but was mainly at 200-500 m, and the flight speed was mainly 7-9 m/s. S. trifoli populations fly mainly in an east-southeast direction. During the peak migration period, northwest airflow was prevalent at high altitudes, with temperatures ranging from 15-28 °C and humidity from 40%-55% at 925 hPa and 900 hPa on peak migration days. [Conclusion] Airflow, high altitude temperature and humidity are the main reasons for the different flight behavior of S. trifoli in the Central Asian insect migration zone compared to that in other insect migration zones in East Asia.