气候变化条件下中国小菜蛾冬季存活和越冬分布研究

The diamondback moth (DBM) is an important pest worldwide. The overwintering survival in different area of China remaines unclear. This issue is significant for its early prediction and pesticide resistance management. The winter distribution of non-diapause insects,eg.DBM, under context of climate change is a hot issue in global change biology. This project aims at establishing a model to describe overwintering survival and winter distribution of DBM by using ecological methodology. We would select 10 locations at different latitudes and establish models to describe temporary dynamics of winter temperatures. We would create these temperature regimens with climatic chambers and test survival of DBM. We would use the data collected in these experiments to establish survival models of DBM including the chronic lethal effects of mild winter and the cumulative injury of low temperatures. Meanwhile, we would conduct field studies in those areas to collect survival data under natural and warming winter conditions. We would also conduct field surveys to discover the natural survival of DBM in the winter. We then validate the survival models with field data. Finally, we predict the geographical distribution shifts of overwintering area of DBM under context of climate warming, based on the optimal survival model and future temperature data. In recent years, the pure ecological studies on pest management become less and less in China, because these studies can hardly been accepted by journals with high impact factors. Here we try to address an important ecological issue, effect of long-term winter warming on insect overwintering through sets of short-term laboratory and field experiments together with modeling works. Our approaches would be helpful to solve the prominent contradiction between long-term chronic climate change and short research lifespan of investigators. Our group has been focused on impact of climate change on insect and their adaptation to climate change for more than 10 years. We are familiar with most advance theory and methodology in thermal biology, climate change biology and modeling in insects. We have collected big body of data in temperature, life history traits, field population densities and GIS. Last year, we started to publish papers on good journals such as Journal of Animal Ecology, Molecular Ecology etc. We have rich experiences on the overwintering of DBM. We reviewed literature on DBM overwintering. We successfully reared the DBM with artificial diet. We preliminarily tested their super-cooling points, survival under different low-temperatures and exposures, survival under field conditions at various loclocations. We found that DBM could not overwinter in areas with cold winter. Our preliminary field survey indicates that DBM only can overwinter sporadically at places with mild winter temperatures. Therefore, we have the confidence to finish this project with a high level of standard.

小菜蛾是世界重要蔬菜害虫。其在我国越冬分布尚无明确结论。能否越冬事关早期预警和抗性治理策略制定。拟用生态学手段阐明小菜蛾为代表的非滞育昆虫越冬分布这一气候变化生物学前沿热点问题。选择不同纬度10个地点建立冬季温度变化模型，模拟试验小菜蛾存活；构建包括温和冬季慢性致死效应及低温伤害累积效应的存活模型；田间越冬试验检验模型有效性；结合温度变化数据预测冬季变暖下越冬区域地理变迁。通过室内外短周期试验，阐明长周期冬季变暖对越冬的生态效应，解决气候变化长期性与科研人员时间有限性之间的突出矛盾，突破农业昆虫与害虫防治学科中纯生态学研究耗时费力难以发表高影响因子论文的瓶颈。申请团队掌握了相关前沿理论、实验方法，系统调研了小菜蛾越冬文献，测定了过冷却点、结冰点和低温存活率，在部分地区试验了田间越冬存活，积累了大量实验、气候及GIS高程数据和气候驱动昆虫种群动态模型。这些基础使我们有信心高水平完成项目。

本项目采用历史气候分析及未来气候情景模拟的方法，利用实验室模拟、田间调查、模型构建等生态学研究手段，阐明以小菜蛾为代表的非滞育昆虫越冬分布及未来气候变暖下小菜蛾越冬区域的变迁。1）选择了不同纬度具有代表性的10个地点，模拟其冬季温度变化曲线，开展了室内越冬模拟试验，并进行了田间越冬调查，研究了不同冬季气温模式下的极端和自然低温的存活率，明确了小菜蛾在中国吉林至长江流域之间的越冬状况。2）模拟了冬季不同低温和食物模式下小菜蛾不同龄期幼虫的抗寒性，明确了低温冷害和低温下食物摄入是小菜蛾能否安全越冬的重要限制因子。3）利用过冷却点及自然低温存活模拟试验所得数据，构建了基于不同类型低温指标的小菜蛾越冬存活模型；利用田间存活调查数据检验模型有效性，确定了最优的的小菜蛾越冬存活模型为累积“低温冷量”存活模型。4）结合温度变化数据和越冬存活模型，预测未来冬季变暖下小菜蛾成功越冬区域将继续北移。本项目在研究方法上具有创新性，克服了传统田间试验的局限，为气候变化生物学中的“温度与物种分布”研究开辟一条新途径。研究思路和模型构建方法在研究气候变化对非滞育昆虫越冬及分布的影响，以及预测气候变化下非滞育昆虫的种群动态方面具有潜在的应用价值。