【作者】 韩兰芝；

【导师】 翟保平；

【作者基本信息】 南京农业大学 ， 农业昆虫与害虫防治， 2004， 博士

【摘要】 从80年代中后期开始，甜菜夜蛾连续多年在我国各省份爆发成灾，成为农业生产上的一种灾难性害虫。已有研究报道甜菜夜蛾是一种远距离迁飞害虫，但尚未定论；对甜菜夜蛾飞行的生理、生态机制以及遗传因素对其飞行能力的影响，至今仍知之甚少。本文从甜菜夜蛾的迁飞特性入手，对其生态适合度、抗寒和越冬能力、生殖、遗传和环境因子对其飞行能力及再迁飞能力的影响、虫源性质及迁飞轨迹分析、飞行能源物质的代谢酶等方面进行了系统研究，获得如下结果： 通过组建甜菜夜蛾在5种温度下(20℃、23℃、26℃、29℃、32℃)的实验种群生命表，得出甜菜夜蛾在不同温度下的生态适合度。结果表明：在20-32℃，甜菜夜蛾的发育速率随着温度的升高而加快，并符合Logistic模型；甜菜夜蛾卵、幼虫、蛹、产卵前期及世代的发育起点温度分别为13.73℃、15.68℃、15.09℃、12.83℃和15.06℃，有效积温分别为37.9、126.3、73.8、29.2和265.60日·度；甜菜夜蛾在26℃时世代存活率和种群增长指数最高，分别为55.2％和205.9，20℃时不利于种群增长；在26℃和29℃时，甜菜夜蛾的平均产卵量最高，分别为604.7和611.4粒/雌，26℃是甜菜夜蛾最适宜交配的温度，交配率为84.9％，平均精包数为2.46个/雌；高温条件下，甜菜夜蛾的成虫寿命、产卵前期和产卵期均缩短；甜菜夜蛾的世代存活率(S)和种群趋势指数(I)与温度(t)的关系可用二次抛物线表示：S=-0.5056t~2+27.652t-326.02(r=0.91)，I=-3.2532t~2+178.45t-2270.40(r=0.94)。 测定了河北隆荛、湖南衡阳和江苏南京三个地理种群甜菜夜蛾的过冷却点和结冰点，并进行了埋蛹越冬试验。结果表明，甜菜夜蛾蛹的过冷却点最低，过冷却现象也最明显，因而蛹是甜菜夜蛾最适宜越冬的虫态。三个地理种群中，以湖南衡阳的抗寒能力最强，其次为河北隆荛和江苏南京。连续两年的田间埋蛹越冬试验表明，甜菜夜蛾不大可能在南京越冬。 通过室内卵巢逐日解剖试验，将甜菜夜蛾卵巢发育进度分为五级，即乳白透明期(Ⅰ)、卵黄沉积期(Ⅱ)、成熟待产期(Ⅲ)、产卵盛期(Ⅳ)和产卵末期(Ⅴ)。卵巢发育进度与日产卵量呈明显的相关性。与其他迁飞性昆虫相比，甜菜夜蛾的卵巢发育比较快，在蛹末期已发育为二级，羽化第二天，三级卵巢所占比例为65％。甜菜夜蛾产卵前期比较短，27℃下，补充营养和未补充营养的甜菜夜蛾的产卵前期无显著差甜菜夜蛾迁飞的生态机制研究异，分别为2.40士1 .06d和2.58士1 .24 d. 生殖隔离条件下，不同日龄甜菜夜蛾的飞行能力存在一定差异。初羽化时，甜菜夜蛾就具有一定的飞行能力，3、4日龄时其飞行能力最强。但未交配的雌虫卵巢发育特别缓慢，并且产卵量非常少，羽化第2、3天，其卵巢发育级别均为三级;羽化第4天，三级卵巢比例仍在90%以上，且尚未产卵;羽化第5、6天，三、四级卵巢比例各占50%左右，有少数卵产出。自然交配条件下，以2日龄和7日龄蛾的飞行能力较强。交配后，卵巢迅速发育。羽化第2天，三级卵巢比例为80.”%;羽化第3、4天，四级卵巢比例分别为50%和68%，许多卵已产出;羽化第5、6天，五级卵巢比例上升;习习化第7天，五级卵巢比例已达80%。此时，大部分蛾子已排完卵.这说明交配能刺激雌蛾卵巢发育。 同一日龄交配和未交配条件下，除4、7日龄的平均飞行时间存在差异外，其余日龄的飞行能力均没有显著差异。说明交配并不能影响成虫的飞行能力，而且雌蛾的怀卵量与飞行能力也不存在显著相关。因此，甜菜夜蛾不存在其他迁飞昆虫所具有的 ，’9尸子发生与飞行共扼”现象。 饲养期间光周期的长短和3一5日龄幼虫周期性饥俄对甜菜夜蛾飞行能力没有显著影响。不同饲养温度(20℃一30℃)对甜菜夜蛾飞行持续时间和飞行距离有显著影响，饲养温度越高，飞行能力越强。 根据飞行持续时间(吊飞12h)将甜菜夜蛾种群划分为居留型(<5 omin)、迁飞型(>somin)、强迁飞型(》25omin)和再迁飞型(第二次吊飞飞行持续时间仍>50min):在所有吊飞个体(684头)中，供试虫的起飞比率为43.6%(298头)，起飞个体中的再迁飞比例为503%(150头)。5日龄蛾在生殖隔离和自然交配条件下的迁飞型比率存在显著差异(U二1.9800，P<0.05)，但其他日龄的迁飞型比率均未达到显著差异(U二0.4320，1 .5389，0.5868，P>0.05)。甜菜夜蛾的迁飞型个体均最多可进行4次再迁飞，其再迁飞型比率随着再迁次数的增多而逐渐降低，且强飞个体表现较强的再飞能力;不同日龄间的再迁飞型比例存在一定差异，生殖隔离和自然交配种群随着龄期的增加，其再迁飞型比率并没显著下降。 通过田间调查、灯诱和性诱资料表明，甜菜夜蛾在江苏丰县一年可发生五代;四月初黑光灯下始见越冬代蛾，十月下旬终见末代蛾;从三代开始出现世代重叠。幼虫以三四代为害最为严重;田间卵峰日通常比蛾峰日落后2一3天;成幼虫喜欢在幼嫩植林上产卵、取食且卵块多位于叶片背面，特别是趋向在丰县主栽蔬菜一芦笋上产卵。甜菜夜蛾迁飞的生态机制研究.中文摘要 气候资料分析表明，甜菜夜峨在江苏丰县基本上不能越冬，即使个别暖冬年?更多还原

【Abstract】 The beet armyworm, Spodoptera exigua (Hubner), is a polyphagous pest with worldwide distribution mainly in tropical and subtropical regions. In recent years, the beet armyworm has risen to the status of an economically important pest of many kinds of crops in China, especially in the northern part of the country. The long distance migration of the beet armyworm has been reported based on some indirect evidences. Our understandings on the genetic, physiological and ecological factors affecting flight capacity of the moths are still very poor.. In this paper, the ecological mechanisms of beet armyworm migration were explored, including population status, ecological fitness, cold hardiness and overwintering, reproduction and flight syndrome, re-emigration capacity, genetics of flight capacity and activities of enzymes in energy metabolism. The results were summarized as follows.Life tables of laboratory population at five different temperatures were constructed. The results showed that the developmental rate increased with temperature from 20# to 32#, and the relationship could be simulated by a logistic model. The developmental temperature thresholds and sum of degree-day accumulation required for egg, larva, pupa, preoviposition stages and generation were 13.73#, 15.68#, 15.09#, 12.83#, 15.06#, and 37.9, 126.3, 73.8, 29.2, 265.6 degree day respectively. Survival rate of immature stage, mating rate of adults and population trend index were the highest at 26#. Mean egg productions at 26# and 29# were 604.7 and 611.4 respectively. Adult longevity, preoviposition and ovipositon periods declined at high temperature. Relationship between generation survival rate (5), population trend index (I) and temperature (t) could be descried by the equations: S= -0.5056 t2+ 27.652 t - 326.02, I= -3.2532 t2+ 178.45t - 2270.40.Supercooling points and freezing points at different developmental stages of the beet armyworm for different geographical populations were measured with a thermocouple. Supercooling points of pupae were the lowest and its supercooling phenomenon was also the most obviously, so pupa is the most possible stage for overwintering. Cold hardiness of the population from Hengyang, Hunan Province was the most powerful, followed by Longrao population (Hebei Province) and Nanjing population (Jiangsu Province).Overwintering survival rate estimated by field trials with pupae burying suggests that the beet armyworm could not possibly overwinter in Nanjing.Ovarian development of beet armyworm was classified by ovarian dissection, including transparent stage (grade I, before 5-days old pupae stage), vitellogenesis stage (grade II, late pupae and newly emerged moths), matured stage (grade III, the 2nd and 3rd day after emergence), egg-laying stage (grade IV, the 4th and 5th day after emergence), late egg-laying stage (grade V, since the 6th day after emergence). There was obvious correlation between ovarian development and the amount of egg-laid. The ovarian development of beet armyworm is characteristic of a quite short preoviposition stage (2.40 +1.06d). The second grade would be seen in the late stage of pupae and 80% of the individuals emerged in the second day after emergence would be with mature eggs (grade III and IV), among which 15% of the moths with the 4th grade ovary had laid their eggs.Flight capacity of the virgin moths at different ages was significantly different. The maximum flight activity were performed by 3 and 4 days old moths, although the newly emerged moths could also flight a while, Ovarian development of virgin females was slowly and no eggs were laid until the 5th and 6th day after emergence when a few eggs were laid. But mated moths showed quick ovarian development that more than 50% of the females had laid eggs at 3 days old, meanwhile, the strongest flight capacity appeared on the 2nd and 3rd day after emergence. The tethered tests demonstrated that flight ability of virgin and copulated moths at the same ages showed no difference, and that there were no significant correlations b更多还原