华北北部地区二代棉铃虫成虫迁飞行为的雷达观测

Radar observations on the migratory behavior of the second generation cotton bollworm moths in the north part of northern China

迁飞习性是棉铃虫区域性灾变的生物学基础,明确棉铃虫的迁飞行为对发展预警技术有重要的意义。2000年7～8月华北地区棉铃虫大发生期间,利用昆虫雷达和空中诱虫灯在河北省廊坊市观测研究了棉铃虫成虫的迁飞行为。试验结果表明,与地面棉铃虫相比,高空棉铃虫具有明显的迁飞昆虫生理特征。棉铃虫成虫一般在日落后30min(20∶00)左右大量起飞,种群密度在1h后达到峰值。此后,随着成虫的大量迁出,空中密度逐渐下降。棉铃虫成虫从低空到高空起飞过程中位移方向多呈顺时针旋转,借助夏季盛行风飞行。成虫飞行成层多集中在200～300m高度,最髙可达1000m。多数个体位移速率35～45km/h,整个夜间的迁移活动持续7～8h,迁移距离大约250～450km。

The migratory behavior of Helicoverpa armigera （Htibner） is a key factor resulting in its regional outbreak in China, and the understanding for relationship between migratory activity of the pest and climate environment is essential for establishing a population forecasting system. The migratory behavior of the second generation moths of Helicoverpa armigera was observed with insect radar in July and August 2000 at Langfang, Hebei Province. Alongside, a vertical pointing searchlight trap and a conventional light-trap were simultaneously operated to sample insect populations from high altitude and from near ground level respectively. Ovarian development analysis on the moths captured indicated that H. armigera population from high altitude was comprised of predominantly young individuals, and showed a typical physiological characteristic of migrating insects. H. armigera moths were observed to take off at dusk （20： 00）, a half hour after sunset, and population density reached peak period in 1 h. Then, the area density decreased gradually as the moths emigrated. The moths generally ascended to altitudes of up to 1 000 m above ground level （AGL） with directions spiral clockwise up to high altitude, and formed main migrating layers at 200 - 300 m AGL. In most cases, the moths displaced at speed of 35 - 45 km/h and lasted 7 -8 h in one night with the migration distance of 250 -450 km.