【作者】 王小平；

【导师】 游兰韶； 戈峰； 薛芳森；

【作者基本信息】 湖南农业大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 大猿叶虫Colaphellus bowringi Baly 1865属鞘翅目Coleptera，叶甲科Chrysomelidae，无缘叶甲属Colaphellus，是我国十字花科蔬菜上的一种重要食叶害虫。本研究的大猿叶虫江西种群以成虫在土壤中越冬和越夏。由于成虫滞育期的差异，该虫的化性显示了明显的种内变异。有些个体隔年繁殖；有些个体是一化性的，仅在春季或秋季繁殖1代；有些个体是二化性的，春季和秋季各繁殖1代；有些个体是多化性的，春季1代，秋季2-3代。因此，大猿叶虫在田间一年可发生4代。大猿叶虫是短日照型昆虫，但它的光周期反应主要取决于温度，当日平均温度≤20℃时，不论光周期条件如何，所有个体进入滞育。滞育抑制的短日照效应只有在较高温度下(＞20℃)才能表达。 本论文以大猿叶虫为材料，不仅较详细研究了外界环境因子对滞育诱导的影响，也较系统研究了滞育持续期对滞育解除后生物学特性及其子代繁殖的影响。结果分述如下： 1、大猿叶虫滞育诱导和钟机制的研究 24-h昼夜循环的光周期反应显示了大猿叶虫是一个典型的短日照型昆虫。在25℃和28℃下，临界暗长介于10h至12 h之间。非24-h昼夜循环的光周期反应曲线表明暗期的长度在滞育的决定中发挥了重要的作用。夜间干扰试验揭示了暗期对光干扰高度敏感。Nanda-Hamner试验的光周期反应曲线呈现了三个以24 h间隔的滞育诱导峰。Bthasow试验的光周期反应则没有显示滞育诱导的节律性。因此，昼夜节律系统(circadium system)仅构成了大猿叶虫光周期钟的一部分。在该虫滞育诱导的敏感期内，光周期的计数器可积累长夜信息也能积累短夜信息，但积累的方式不同。 2、温周期对大猿叶虫滞育诱导的作用 在缺乏光的条件下(DD)，大猿叶虫温周期反应的临界低温持续期约为10.5 h。恒温反应曲线和温周期反应曲线均显示了滞育的发生主要取决于日平均温度，日平均温度≤20℃时，所有个体进入滞育，＞20℃时，随日平均温度升高滞育的发生逐渐下降。低温期反应阈值温度约为19℃，温期反应阈值温度约为31℃。在日平均温度为22℃，23℃和24℃下，温周期幅度对滞育诱导具有显著影响，但当日平均温度≥25℃时，温周期幅度对滞育诱导没有显著作用。在LD12：12下，温周期滞育的诱导受到光期温度的强烈影响；温周期在LD12：12下的滞育发生低于持续暗期下的滞育发生。 3、食料对大猿叶虫滞育诱导的影响 在25℃、LD13：11条件下，大猿叶虫取食小白菜A(苏州青)Brassica chinensis Var. communis、萝卜叶Raphanus sativus var.longipinnatus、茎用芥菜叶B. juncea var. tumida和小白菜B(上海青)B. chinensis var.communis滞育比例依次降低;取食衰老叶片趋于诱导滞育。食料对大猿叶虫滞育诱导的影响仅在一定的温度和光周期范围内才会表达出来。对不同寄主叶片营养成分含量测定，分析表明，叶片中脂类和叶绿素分别与水分相互作用调节滞育的发生。 4、光周期和温度对滞育后成虫生物学特性的影响在25℃下，光周期(LD 14:10和LD12:12)对成虫滞育后的生殖力、存活率、寿命、总产卵量、平均产卵量均无显著影响。在长日照(L D14:10)下，温度(18℃，22℃和25℃)对滞育后成虫的生物学特性具有明显的影响，随温度的降低，总产卵量随温度下降呈降低趋势，但无显著差异;平均产卵量随温度下降而显著降低;滞育后雌虫寿命亦随温度降低显著延长，但雄虫滞育后寿命差异不显著。18℃下少量个体被再次诱导滞育。 5、大猿叶虫滞育持续期对其滞育后生物学特性的影响在自然条件和恒定条件下，对非滞育和自然滞育持续期约为5、9、16、22、29、34、47个月的大猿叶虫成虫寿命和生殖力进行了测定。结果表明，非滞育成虫的寿命显著长于经历约5、9、16个月滞育的成虫滞育后寿命，但不显著长于经历约22、29、34、47个月滞育成虫。非滞育雌虫具有长的产卵前期和产卵期，其每雌总产卵量、早期产卵量、平均产卵量和每日的产卵量显著低于经历滞育的雌虫(经历约5个月滞育的雌虫除外)。在经历滞育的个体中，产卵前期差异很小，每雌总产卵量、早期产卵量、平均产卵量和滞育后寿命、产卵期以滞育期22个月的雌虫最高或最长，滞育期29一34个月的雌虫次之，滞育期5一16个月的雌虫最低。 6、大猿叶虫亲代滞育持续期对其子代繁殖的影响在25℃、LD12:12条件下，测定了大猿叶虫亲代滞育持续期(约5、9、22、34个月)对其子代生物学特性的影响。不同亲代卵孵化率，及子代蛹存活率、产卵量、非滞育成虫寿命均无显著差异。非滞育亲代的卵和子代幼虫发育似乎需要更长时间，但其非滞育成虫寿命较短。亲代经历约34个月滞育的子代卵和幼虫发育时间短，但蛹期较长。非滞育亲代的子代幼虫存活率显著低于亲代经历滞育的子代幼虫，亲代滞育持续期对子代幼虫存活率影响不显著。非滞育亲代的子代成虫滞育发生显著低于亲代经历滞育的子代成虫。 研究结果表明，光周期、温周期和食料因子对大猿叶虫滞育诱导的调节作用，决定了该虫春季发生一代、秋季发生三代。大猿叶虫成虫个体间寿命、生殖力和滞育持续期的变异，以及滞育持续期对子代繁殖的影响，构成了该虫分散适应策略的一部分。更多还原

【Abstract】 The cabbage beetle, Colaphellus bowringi Baly 1865 (Coleptera: Chrysomelidae) is a serious pest of crucifers in China. The beetle’s population in Jiangxi Province enters summer and winter diapause as adults in the soil. There are two distinct infestation peaks in the field, one in spring and a second in autumn. The beetle showed a considerable intrapopulation variation in its life history due to the difference in duration of diapause. Some individuals took more than one year to produce one generation. Some were univoltine, i.e., only one generation in spring or autumn; Some were biovoltine, i.e., one generation in spring, another in autumn; Some were multivoltine, i.e., one generation in spring, two or three generations in autumn. Thus, there are four generations per year in the field. The cabbage beetle is a short-day species, but its photoperiodic response highly depended on temperature. All adults entered diapause regardless of photoperiods if the mean temperature was ≤ 20℃; Whereas the diapause-averting influence of short daylengths was expressed only at high temperatures (above 20℃).In this thesis, the effects of environmental factors on diapause induction and diapause duration on the post-diapause life-history traits and offspring performance were investigated in the cabbage beetle.1. Diapause induction and clock mechanismThe cabbage beetle, C. bowringi is a short day species. Using 24-h light-dark cycles, the photoperiodic responses at 25 and 28癈 revealed a critical nightlength between 10 and 12 h. Using non-24-h light-dark cycles, it showed that the duration of the night was much more important than the duration of the light phase in diapause determination. Night-interruption experiments with T = 24 h showed that diapause was effectively induced by a 2-h light pulse in most scotophases; whereas day-interruption experiments by a 2-h dark-break had a little effect on the incidence of diapause. Nanda-Hamner experiments displayed three declining peaks of diapause at 24 h circadian intervals. Bunsow experiments showed two very weak peaks for diapause induction, one being 8 h after lights-off, and another 8 h before lights-on, but it did not show peaks of diapause at a 24 h interval. These results suggest that the circadian oscillatory system constitutes a part of the photoperiodic clock of this beetle but plays a limited role in its photoperiodic time measurement. The experiments of alternating short-night cycles (LD 16:8) and long-night cycles (LD 12:12) during the sensitive larval period showed that the ’counter’ in C. bowringi accumulated long nights as well as short nights, but in different ways.2. Effects of thermoperiod on the diapause inductionThe diapause response curves at the thermoperiod (C:T16:28℃) under continuously darkrearing conditions revealed that the critical cryophase duration was of about 10.5 h. The diapause response curves both at different constant temperatures and at the thermoperiod under continuously dark rearing conditions clearly showed that the incidence of diapause mainly depended on whether or not the mean temperature was ≤20℃ or >20℃. If the mean temperature was ≤20℃, all individuals entered diapause; if >20℃, the incidence of diapause gradually declined with increasing mean temperatures. The results demonstrated a cryophase threshold temperature of about 19℃ and a thermophase threshold temperature of about 31℃ in this insect. Thermoperiodic amplitude (temperature difference between cryophase and thermophase) was shown to have a significant influence on diapause induction at the mean temperatures of 22, 23 and 24℃, but not at ≤20℃ and at > 25℃. Thermoperiodic responses at LD12: 12 clearly showed that the incidence of diapause was strongly influenced by the photophase temperature. The thermoperiod at LD12:12 induced much lower incidence of diapause than the thermoperiod with the same temperature at continuous darkness.3. Effects of food-plants on the diapause inductionIn the cabbage beetle, C. bowringi, the incidence of diapause w更多还原