草地螟迁入和再迁飞种群的生理环境特征分析

The physiological and environmental aspects of an immigrant and re-emigrant population of beet webworm,Loxostege sticticalis

为了进一步阐明草地螟的迁飞危害规律,研究了2012年6月迁入河北康保城关的成虫种群消长过程,并分析了主要生理特征及环境条件与之的关系。结果显示:黑光灯单灯诱蛾量由6月16日的561头增加到17日的3 451头,但18日和19日的诱蛾量则下降到1 771头和118头,田间百步惊蛾量由17日的3 000头下降到19日的60头;虽然迁入地具有适宜的温度和蜜源条件,但由于其环境湿度太低(42%),不利于成虫生殖是成虫再迁出的主要原因。迁入成虫卵巢级别在2～4级之间,17日具3级卵巢的成虫比例显著多于19日的,而具4级的显著少于19日的,但具2级的在17、18日和19日之间没有显著差异。这3天的成虫性比无显著差异,成虫交配率均在80%以上,但19日的成虫交配率显著高于17日的。这些结果较好地阐明了草地螟田间迁入和再迁飞种群的生理行为特征及环境条件。

To understand the migratory behavior and physiology of the beet webworm, Loxostege sticticalis L., the population dynamics, major physiological characteristics, and environmental conditions for an immigrant adult population were investigated in Kangbao County through June 17 to 19 of 2012. The number of moths caught by the black-light trap increased from 561 on June 16 to 3 451 on June 17, but dramatically dropped to 1 771 and 118 on June 18 and 19, respectively. Synchronously, the number of moths encountered in the field by 100 paces was 3 000 on June 17 but declined to 60 on June 19, respectively, indicating that the moths emigrated shortly after im- migration. Low relative humidity （RH） was considered as the major cause for the re-emigration of the adults be- cause the ambient RH was only 42% for June 17 to 18. The ovarian development of all females caught was from stage 2 to 4 （larger number indicates more mature ovary）. The proportion of females in ovarian development stage 3 decreased while that of stage 4 was significantly increased from 17 to 19. However, the proportion of females in stage 2 and the sex ratio of the moths were insignificantly different during the 3-day period. The mating percent- age of the moths was over 80% and increased daily from 17 to 19. Consequently, the percentage of moths mated on June 19 was significantly greater than that on June 17. Thus, the physiological and environmental characteris- tics of an immigrant and re-emigrant population were demonstrated by these new findings.