氮素含量对亚洲玉米螟取食及选择性影响

【目的】研究亚洲玉米螟幼虫对不同氮素含量取食和选择特性,了解植物营养与昆虫选择之间的关系,为亚洲玉米螟幼虫的取食、选择提供理论依据。【方法】采用室内采用叶碟法对亚洲玉米螟进行取食选择实验,计算取食率;在室外人工模拟设计出5个氮肥施肥量处理,调查玉米螟的危害情况。【结果】亚洲玉米螟幼虫在 48 h 非选择实验中,接虫2 h后,在对照(N含量10.69%)和N₄(18.84%)的取食率最高,为58%,接虫第4~6 h,取食选择性依次为N₃>N₅>N₄>N₁>N₂,初孵幼虫在N₄(18.84%)的第8、12、36和48 h的取食率最高,依次为70.5%、67%、61.5%、63.5%;N₄(18.84%)上的取食率在36 h时达到最高,为43.3%,比对照高10%,N₅(30.31%)取食率在8 h时达到最高,为46.67%,比对照高20%,差异显著(P<0.05);不同氮素施肥量亚洲玉米螟发生为害中被害株率达到10%以上有2个处理,其中被害株率最高的是50 kg/667m²,达到22.89%,其次是40 kg/667m²为12.67%,二者差异不显著(P>0.05),但是与其他处理之间差异显著(P<0.05)。【结论】不同N素含量对亚洲玉米螟幼虫取食、选择具有显著影响,但是存在一定阈值,超过该值以后,取食率、被害株率等相对数据可能保持平稳或者往相反的方向发展。

Effects of Different Nitrogen Contents on Population Proliferation of Asian Corn Borer

【Objective】 To clarify the effects of artificial diets with different nitrogen contents on the growth, development and reproduction of the Asian corn borer (Ostrinia furnacalis), in the hope of providing some theoretical basis for the feeding and selection of Asian corn borer larvae. 【Method】 Two methods were adopted in the study: in the laboratory, food selection experiment on Asian corn borer was conducted by leaf dish method to calculated the feeding rate; Outside, five different nitrogen content feeds with nitrogen content of 3.94%, 7.33%, 10.69%, 18.84%, and 30.31% were set to determine the effects of different nitrogen content on the growth and development of the Asian corn borer. 【Results】 At 25℃ the low nitrogen level N₁ (nitrogen content 3.94%) failed to emerge normally, and the larval development period was the longest. When the nitrogen content increased to 18.84% (N₄), the intrinsic growth rate (0.13) and net proliferation rate (66.14), weekly growth rate (1.14), hatching rate (90.06%) was the highest, average generation period (30.79), population doubling time (5.17) was the shortest, which was significantly different from the other four nitrogen levels (P<0.05), the larval duration was significantly shortened, the N₄ pupation rate (98.66%), emergence rate (95.45%), survival rate (91.33%), and average egg production per female (120.12±9.73) were the highest, but when the nitrogen content after reaching 30.31%, the intrinsic growth rate (0.04), net multiplication rate (44.71), and weekly growth rate (1.04) were the lowest, the average generation period (92.36), and the population doubling time (16.85) was the longest, at 25℃ and, the result at 30℃ was close to that at 20℃. In addition, there was no significant difference in the pupal stage, adult moth lifespan, and female fecundity between the three temperature treatments (P>0.05). 【Conclusion】 Nitrogen content is closely related to the individual development of the Asian corn borer and the population multiplication. In a certain interval, with the increase of nitrogen content, the growth speeds up and the population multiplication ability is enhanced. High nitrogen 30.31% and low nitrogen 3.94% both have a significant inhibitory effect on the growth of corn borer.