【作者】 王雪；

【导师】 叶乐夫；

【作者基本信息】 东北农业大学 ， 农业昆虫与害虫防治， 2021， 硕士

【摘要】 异色瓢虫Harmonia axyridis,作为被广泛应用于生产实践的捕食性天敌昆虫,不同于其它天敌种类,在某些特定的区域,异色瓢虫能够大规模发生,并可以入侵各类农林草生态系统,与一些当地的天敌种类竞争资源,造成天敌群落的物种单一化,进而影响天敌整体控害功能的稳定性。异色瓢虫的爆发,推测与其个体生存能力(包括捕食能力和逃避天敌的能力,以及在非生物逆境因子下的特殊响应模式),以及种内两性关系及种群繁殖力方面有其特殊性相关。为探究异色瓢虫区域性爆发的原因,我们首先在秋季调查了寒地黑土区农林生态系统中异色瓢虫的成虫自然种群,探讨了种群内个体的底色构成及种群性别比例规律;在室内构建了不同底色的雌雄配对处理,还增加杀虫剂的处理因子,测度其后代的底色及性别构成;结合自然种群的参数,计算下一代“假想种群”的底色及性别构成;此外,还以不同的雌雄比例构建室内成虫(新羽化2天内)种群,观察成虫寿命、产卵量,孵化率、发育历期等生命表参数。试验主要研究结果如下:(1)在无杀虫剂施用的农林生态系统中,异色瓢虫自然种群成虫雌性占比为51±2.2%,黄底鞘翅个体占比为85±1.8%,雌性中黄底个体占比为84%,显著低于雄性中黄底个体的占比(87%),相应的黑底鞘翅个体占比为15%。在下一代假想种群中,若无杀虫剂处理,异色瓢虫成虫雌性占比与上一代持平(52%),黄底鞘翅个体占比为85%,也与亲代相一致;在接触药剂的处理中,成虫雌性占比上升为60%,黑底鞘翅个体占比上升为26%。性比为(3:7),(5:5),(7:3),(9:1)的人工种群的子代雌性占比分别为59%,52%,51%,57%。(2)性比为(5:5)的人工种群,每雌产卵量最大,为659±32枚,性比为(3:7),(7:3),(9:1)的处理产卵量分别为353±27,461±20,502±53枚;雌虫寿命较长,为86±6 d,性比为(3:7),(7:3),(9:1)的处理雌虫寿命分别为54±3 d,93±5 d,115±4 d;子代幼蛹发育历期最短,为16.00±0.23 d,性比为(3:7),(7:3),(9:1)的处理幼蛹发育历期分别为16.73±0.35 d,17.06±0.27d,16.32±0.14d;综合每雌单日增长率(与内禀增长率相似)为其他性比处理的1.7倍。结论:异色瓢虫在寒地黑土区农林生态系统中发生数量较大,部分原因在于面临逆境因子选择作用时,雌性比例会相应上升,保持较高的种群增殖能力;逆境解除后,通过一代繁殖,雌性占比就会恢复到50%左右,而50%雌性的种群单雌增殖率远高于其他雌性比例的种群,此时种群发展潜力最大。其次,当面临杀虫剂等非生物逆境因子时,异色瓢虫黄底鞘翅个体在种群中的占比下降,黑底个体占比上升;雌性比例显著增加,因此,异色瓢虫多样化的体色构成及性比对环境压力能作出灵敏的响应变化,能很好的反映环境质量(是否存在杀虫剂等胁迫因子),可以作为一种很有潜力的环境指示生物。更多还原

【Abstract】 Harmonia axyridis,as a predatory natural enemy insect species applied widely in production practice,is different from other enemy insect groups.In some areas,it occurred on a large scale and successfully invaded nearly all kinds of agroforestry and grass ecosystems,competing with local insect enemy species for sources,which caused the species simplification of natural enemy community,therefore affected the stability of natural enemy control function.The explosive occurrence of H.axyridis,is speculated that on the aspects of individual survival ability,including the ability to prey and escape from natural enemies,as well as the special response mode under abiotic stress factors,and the intra species sexual relationship and population fecundity.In order to explore the cause of regional outbreak of H.axyridis,we firstly investigated the natural adult population of H.axyridis in the agroforestry ecosystem in black soil cropping area,and determined the elytral color composition and sex ratio of the population.In the laboratory,we constructed a pair of female and male individuals with different background colors,as well as the application of insecticide,and we measured the background color and gender composition of its offspring adult.Combining with the above parameters of natural population,we calculated the background color proportion and gender composition of "deduced population"(next generation).In addition,the artificial indoor populations were constructed with different male and female ratio,and the life table parameters were observed,such as spawning amount,hatching rate and so on.Results showed that:(1)In the agroforestry ecosystems without insecticide application,the female proportion of H.axyridis adults was 51±2.2%,the proportion of individuals with yellow elytra was 85±1.8%;among female individuals,the proportion of yellow background was 84%,which was significantly lower than that of male with yellow background(87%).Accordingly,the proportion of individuals with black background of all the individuals was 15%.For the “deduced population” in the control group(without insecticide application),the proportion of female adults of H.axyridis was similar with that of the parent generation(52%),and the proportion of individuals with yellow background was also 85%,which was consistent with that of parent generation;in the treatment of exposure to pesticide,the proportion of female adults increased to60%,and that of individuals with black background increased to 26%.In the artificial population with different sex ratio of(3:7),(5:5),(7:3),(9:1),the female proportion of the offspring were 59%,52%,51%,57%,respectively.(2)The artificial population with sex ratio of(5:5)had the largest number of eggs per female,which was 659±32.The number of eggs laid in the treatment group with sex ratio of(3:7),(7:3)and(9:1)was 353±27,461±20 and 502±53,respectively.In the population with 50% female individuals,the female had middle level life span with 86±6 d,while the sex ratio was(3:7),(7:3)and(9:1),longevity was 54±3 d,93±5 d,115±4 d,respectively.And the larval and pupal development duration of offspring was the shortest,which was 16.00±0.23 d,meanwhile that of treatment with sex ratio of(3:7),(7:3)and(9:1)was 16.73±0.35 d,17.06±0.27 d and 16.32 ±0.14 d,respectively.Besides,the comprehensive daily reproductive rate(similar with the intrinsic growth rate)of the female was 1.7 times that of other sex ratio treatments.Conclusion: H.axyridis survive in agroforestry ecosystem in black soil cropping area with a large number,which is partly due to the increase of female proportion to keep the high population proliferation ability when facing the selection of adversity factors.After the relief of the adversity,the proportion of females will return to about 50% after one generation reproduction,and the reproduction rate per female of 50% female population is much higher than that of other populations with different sex ratio.At this time,the population development potential is the largest.Besides,when faced with abiotic stress factors such as insecticides,the proportion of yellow elytral H.axyridis decreased,while that with black background increased.Therefore,the diversity of body color composition and sex ratio of H.axyridis can respond to environmental pressure sensitively,which can reflect the environmental quality(whether there are pesticides and other stress factors).So it could be used as a potential environmental indicator.更多还原