【作者】 马罡；

【导师】 马春森；

【作者基本信息】 中国农业科学院 ， 作物生态学， 2012， 博士

【摘要】 昆虫是作物生态系统中重要的组成部分，对作物的生长有重要的影响。尽管气候变暖对昆虫有显著影响，但昆虫在长期进化过程中具备了较强的适应能力以应对栖息环境的变化。行为策略在昆虫应对气候变暖中有重要作用。昆虫行为的改变不仅影响其个体发育、繁殖和分布，还直接关系到昆虫种群的发展。深入研究温度变化对昆虫行为及其导致的生态学后果的影响对了解气候变暖下昆虫种群和作物产量的发展趋势有重要的理论和实际意义。本文通过模拟蚜虫在自然界中所处微环境温度时间和空间的变化特征，研究了气候变暖导致的温度升高对两种小麦蚜虫——麦长管蚜Sitobion avenae和禾谷缢管蚜Rhopalosiphum padi避热行为的影响。通过开展气候变暖对麦蚜在其寄主植物上分布影响的田间模拟试验，分析了温度升高与麦蚜在小麦植株上分布的关系。所得主要结论如下：1.明确了温度预适应对麦蚜爬行热逃逸温度的影响。温度升高，高温持续时间增加，以及未来日间持续高温的情景均使两种麦蚜的爬行热逃逸温度降低。2.明确了温度预适应和饥饿对麦蚜跌落热逃逸温度的影响。较高的温度32°C或超过24h的持续36°C高温预适应后麦长管蚜的跌落温度显著降低，表明经历高温的蚜虫更容易跌落，其在温度逐渐升高过程中的跌落行为可能是一种体温调节行为。蚜虫在同时面临高温和饥饿两种胁迫时存在一种权衡。但蚜虫的耐饥饿能力较差，其通过能量获得调节对高温跌落行为反应的能力十分有限。3.明确了温度升高对麦蚜在小麦植株上分布的影响。旗叶上的两种麦蚜在叶片正面分布的比例随生长季温度的升高而逐渐减小。在未加热的处理下，麦蚜混合种群在叶片正面和反面数量分布的比例相差不大，而在加热处理下，分布在小麦叶片上的麦蚜混合种群在叶片正面分布的比例降低。安阳、北京和临汾三地的小麦蚜虫混合种群在小麦穗部分布的比例在气温较高的年份有所降低。与未加热处理相比，加热处理下小麦植株的株高和旗叶长均较小，小麦的千粒重和亩产量有所降低。本文所得结果意味着在未来气候变暖下蚜虫的避热行为必将增多，而蚜虫采取避热行为时在短时间内无法获得能量，因此将加重对个体发育和种群增长的不利影响。本研究所得结果有助于了解气候变暖下小麦蚜虫在麦类作物上的分布和转移规律，对生产实际中麦蚜种群调查的田间抽样和防治有重要的理论指导意义。更多还原

【Abstract】 Insects are of significant importance to be a part of crop ecosystems. They have a major impact oncrop growth and yield. Climate warming has been known to have a significant effect on insects.However, in the long-term process of evolution, insects have owned strong ability to adapt to thechanging habitats. Behavioral strategies have been proved to play an important role in insects’responses to buffer the pressure arisen by climate warming. Changes in insect behaviors not only impacton their individual growth, reproduction and habitat selection, but also affect on their populationdevelopment. Therefore, the changes in insect behaviors caused by ongoing climate warming and theirecological consequences should be more concerned. Walking and dropping are the main behaviors ofaphids in nature. By simulating the temporal and spatial changes in temperatures within the aphids’microhabitats and defining two parameters to describe the aphids’ heat-escape behaviors by walking ordropping, the effect of simulated warming on heat-escape behaviors of the cereal aphids were studied.The distribution of two aphid species, i.e. Sitobion avenae and Rhopalosiphum padi, within wheat plantinfluenced by temperature change was analyzed. And the relationships between warming and aphids’microhabitat selection were studied. The main results were showed as follows:(1) Temperature acclimation has significant effects on cereal aphids’ crawling behavior, i.e.heat-escape temperatures. Temperature rise, high-temperature duration increase and simulatedcontinuous hot in future decreased the values of heat-escape temperatures for both species. These resultssuggest that climate warming will make the aphids spend much more time and resources to avoidpotential heat injuries to enhance their survival opportunities.(2) Temperature acclimation has significant effects on cereal aphids’ dropping behavior, i.e.drop-off temperatures. The aphids’ behavioral responses to temperature increase showed that DOTwas much higher than start-moving temperature whereas significantly lower than knockdowntemperature, implies that dropping off is a behavioral thermoregulation to avoid heat stress in thecontext of ambient temperature increase. Long-term (12h) starved aphids had much higher DOT thanno/short-term (6h) starved aphids, indicating a trade-off between behavioral thermoregulation andenergy acquisition in the aphids. Higher acclimation temperature (32°C) and longer extremehigh-temperature (36°C) duration (more than24h) significantly lowered the aphids’ DOT, suggests thatthe aphids are likely to avoid heat stress by dropping off host plant when they are exposed to hightemperatures. Climate warming may increase the aphids’ dropping opportunities and consequently affectthe aphids’ individual development and population growth.(3) Temperature rise has great impact on distribution of the aphids on wheat plant. As thedaily temperature of wheat growing season increased, the proportion of both species distributed on thesurface of flag leaf of wheat plant was gradually reduced whereas the proportion of on leaf back wasgradually increased. Under unheated treatment, the percentage that cereal aphids distributed on leafsurface and leaf back differed less. Compared with that under unheated treatment, the proportion ofcereal aphid distributed on leaf surface reduced whereas that distributed on leaf back increased underheated treatment. The proportion of cereal aphid distributed on wheat spike reduced in the three testlocations in2011whereas that distributed on wheat leaf increased, compared with that in2010. Underheated treatment, plant height and length of flag leaf were lower and main stem increased, relative tothat under unheated treatment. Grain weight and yield per mu decreased under heated treatment.These results suggest that climate warming will make the aphids spend much more time and resources to avoid potential heat injuries to enhance their survival opportunities. Climate warming mayincrease the aphids’ heat-escape opportunities and consequently affect the aphids’ individualdevelopment and population growth. Results of this study provided us with valuable information on theeffects of climate warming on aphids’ dispersal and distribution within their microhabitats. The resultsare of great significance to field sampling and pest management.更多还原