旋幽夜蛾迁飞的雷达观测和虫源分析

旋幽夜蛾Scotogramma trifolii Rottemberg是我国北方农牧地区局部暴发为害的农业害虫，近年来危害逐渐呈上升趋势，但目前的研究对其大范围发生危害规律及是否具有迁飞性尚缺乏明确的认识。本文利用垂直监测昆虫雷达和相关辅助设备的长期自动观测和基于GIS的地理信息系统分析，研究了2005年吉林省白城地区通榆县和大安市旋幽夜蛾暴发的虫源性质及成虫空中飞行参数。结果表明：白城地区5月中旬20 cm的平均地温并不满足越冬代蛹羽化的最低温度；2005年5月下旬成虫盛发期东北、华北地区空中风场以南风和偏南风居多，为成虫迁入提供了有利的运载气流。6月下旬雷达观测点卵巢解剖显示，雌蛾卵巢发育进度整齐、级别较低，具有典型的迁出昆虫生理特征。雷达观测显示，成虫飞行最高可达距地面1 000 m, 主要选择在距地面300～500 m高度段，在500 m高度可以整夜飞行。初步判定旋幽夜蛾具有迁飞特性，这一发现为进一步认识其发生规律以及提高其预测预报水平提供了科学依据。

Radar observation and population analysis on the migration of the clover cutworm, Scotogramma trifolii Rottemberg (Lepidoptera: Pyralidae)

The clover cutworm, Scotogramma trifolii Rottemberg is a partially outbreaking pest in farming and stockbreeding areas of northern China. In recent years the pest present uptrend harm to crops. In this paper we reported a long-term monitoring observation of the pest using a vertical-looking radar (VLR) incorporate ancillary equipment and the data analysis by GIS. The results showed that the average soil temperature at 20 cm beneath in the middle ten days of May was lower than the developmental threshold temperature (10.6℃) for eclosion of the hibernated chrysalis. Airflow analysis of the late ten days of May in 2005 showed that south and southwest winds were preponderant in these days, which provided favorable airflow for insect migration. Simultaneous radar observations indicated that the nocturnally migrating clover cutworm generally flew at altitudes of up to 1 000 m above ground level (agl), with high density concentrations at about 300-500 m (agl). They could flight throughout the night at 500 m (agl). The ovarian development of the migrating moths showed typical characteristics of migratory insects. Based on these findings, the factors related to outbreak of this pest in Baicheng of Jilin province were discussed.