桑尺蠖第二代实验种群生命表和幼虫食叶量的测定

THE LIFE TABLE OF THE EXPERIMENTAL POPULATION OF THE SECOND GENERATION OF PHTHONANDRIA ATRILINEATA BUTLER AND DETERMINATION OF THEIR FOOD CONSUMPTION

根据试验数据所组建的桑尺蠖第二代实验种群生命表结果表明,第二代桑尺蠖种群趋势指数为16.054,影响桑尺蠖种群数量变动的主要时期为幼龄幼虫阶段.在自熊温度条件下,卵期5.00天(29.2℃),幼虫期20.34天(26.1℃),蛹期8.28天(27.9℃).幼虫全龄食叶量2720.7mg/头,其中,5龄食叶量占全龄食叶量85%以上,食叶量从3龄起显著增加,5龄平均每日食叶量比4龄增加258.7%.

Adults of Phthonandria atrilineata Butler caught under natural conditions were rearedin the laboratory and the growth and development of the second generation were observedand recorded. A life table established based on the data in the rearing experiment showedthat the trend index of the second generation population of the insect was 16. 054 and thestage of young larvae was the critical period affecting the variation in Ph. atrilineata popu-lation size. Under natural temperature conditions, the egg stage of the insect lasted 5. 00days (29.2℃), the larval stage 20. 34 days (26.1℃) and the pupal stage 8. 28 days(27. 9℃). The mulberry leaf consumption by the insect throughout its larval stage aver-aged 2720. 7 mg/insect and the consumption during the 5th instar accounted for over 85%of the total. Significant increase in leaf consumption started at the 3rd instar, and the av-erage daily leaf consumption during the 5th instar increased by 258. 7% as compared withthat during the 4th instar.