角倍蚜越冬若蚜的生物学特性

【目的】角倍蚜Schlechtendalia chinensis是五倍子蚜的主要生产种，深入了解角倍蚜越冬若蚜的生物学习性，揭示田间无土植藓条件下越冬若蚜的种群动态，可以为进一步降低若蚜越冬的死亡率，提高五倍子产量提供依据。【方法】在田间以无纺布为基质种植侧枝匐灯藓Plagiomnium maximoviczii培育越冬若蚜，定期采集带不同龄期角倍蚜的藓块带回实验室，利用数码显微系统连续观测和记录越冬期间若蚜的行为习性、形态特征、种群动态和龄期分布等，并连续测量越冬期间侧枝匐灯藓的藓层厚度和覆盖率。【结果】角倍蚜秋迁蚜以卵胎生方式产生若蚜，若蚜在侧枝匐灯藓的拟叶基部分泌蜡丝包裹自身并形成蜡球，在蜡球内取食和越冬。每个蜡球内通常有1头若蚜。越冬若蚜从1-4龄，体色由淡黄色逐渐加深至深褐色，体长和体宽随龄期的增加而增加，分别从1龄若蚜552.92±16.95和94.70±11.52μm增加到4龄若蚜的1 205.25±10.75和593.15±7.66 μm。越冬期间若蚜的平均种群密度从10月中旬的13.10×10⁴头/m²降至翌年3月的1.05×10⁴头/m²，总死亡率高达91.98%。越冬若蚜个体间的发育进度很不整齐，并与当地的气温变化密切相关。若蚜越冬期间侧枝匐灯藓的厚度和覆盖率逐步增加。【结论】越冬若蚜体长和体宽可作为角倍蚜龄期鉴别的主要指标。田间越冬期间角倍蚜若蚜的总死亡率很高，其中越冬初期和中期若蚜转移寄生期的死亡率较其他阶段高。

Biological characteristics of overwintering nymphs of the horned-gall aphid,Schlechtendalia chinensis(Hemiptera: Aphididae)

【Aim】 The horned-gall aphid, Schlechtendalia chinensis, is the majorproductive species of Chinese gallnuts. Understanding the biological characteristics andpopulation dynamics of its overwintering nymphs under the condition of soilless moss in thefield will provide a basis for further reducing the mortality of overwintering nymphs andincreasing the yield of Chinese gallnuts. 【Methods】 The overwintering nymphs of S.chinensis were reared in the field on the host moss Plagiomnium maximoviczii which wasplanted on the non-woven fabrics. Mosses with S.chinensis at different developmentalstages were collected regularly and brought back to the laboratory. The behavioral habits,morphological characteristics, population dynamics and instar distributions of S. chinensisnymphs during overwintering were investigated using a digital microscopic system. Thethickness and coverage rate of P. maximoviczii duringtheoverwinteringperiodwere measured aswell. 【Results】 Autumn migrants of S.chinensis reproduce ovoviviparously. The nymphs of S. chinensis excrete wax at the base ofphyllidia of P. maximoviczii and wrap themselves individually to form wax balls where theyfeed and overwinter. Usually there is a single nymph in a wax ball. The body color ofnymphs from the 1st instar to the 4th instar deepens gradually from light yellow to darkbrown. The body length and width of nymphs increased with the nymphal instar, from 552.92±16.95 and 294.70±11.52 μm of the 1st instar nymphs to 1 205.25±10.75 and 593.15±7.66 μm of the 4th instar nymphs, respectively. During the overwintering period, thepopulation density of nymphs dropped from 131 000 aphids/m² in mid-October to 10 500aphids/m² in next March. The total mortality rate was as high as 91.98%. The developmentalprogress of overwintering nymphs was irregular and closely related to the changes of localtemperature. The thickness and coverage rate of the moss layer increased gradually duringoverwintering of S. chinensis nymphs. 【Conclusion】 The body length and body width may beused as the main indicators for the identification of different instars of overwinteringnymphs of S. chinensis. The total mortality rate of overwintering nymphs of S. chinensis inthe field is very high, and the mortality rates during the early overwintering stage andthe middle host-transferring stage are higher than those during the other stages.