气候变暖下南北方夏季高温对小菜蛾种群的影响

Global warming is expected to not only lead to an increase in average temperature but also in the frequency and duration of periods of extreme hot events. Thus, global warming could then lead to a substantial influence on population dynamics of insects, which are always sensitive to temperature changes. By analyzing historical air temperatures, we found that fluctuating patterns of summer daily temperatures are significantly different between the northern and southern parts of China. To clarify the impacts of different temperature patterns on population dynamics of insect pests may be valuable for improving population prediction in different regions under climate warming. In this study, we would simulate typical fluctuating patterns of summer daily temperature in North and South China. Using these patterns, we would examine the temperature effects on development, survival, reproduction and demographic parameters of an global insect pest, the diamondback moth (Plutellla xylostella). In addition, we would investigate the field population dynamics of P. xylostella in Wuhan and Langfang and record the field air temperatures. Combining the previous data of different regions in China collected in our lab for many years, we try to demonstrate the relationship between an increase of summer mean temperature and duration of periods of extreme hot events and population dynamics of P. xylostella in North and South China. We have sufficient research experience on thermal ecology of P. xylotella and other insects, and our research ideas and methods have novelties relative to current studies.

气候变暖导致平均温度升高，夏季极端高温事件频发且持续时间延长，对温度敏感的昆虫有极为重要的影响。通过分析历史数据，我们发现南北方夏季高温波动模式截然不同。揭示南北方夏季高温的差异对害虫种群的影响，对预测气候变暖下害虫在不同地区的发生趋势有重要理论价值和实际意义。本项目拟以重要农业害虫小菜蛾为研究对象，设计中国南北方夏季高温的典型模式，研究模拟基于平均温度升高和高温持续日数增加两个典型特征的南北方夏季高温模式对小菜蛾个体和种群统计学的影响。并在具有南北方气候特征的典型地区，系统调查田间小菜蛾种群动态并收集气象数据，同时结合已有的多年不同地点的田间虫情数据分析，阐明夏季平均温度升高和极端高温持续日数延长与南北方小菜蛾种群动态波动特点的关系。申请人已经从事小菜蛾等昆虫高温生态学研究近7年，在研究气候变暖下极端高温事件对小菜蛾等昆虫影响的研究思路和方法上具有良好基础和国际视野。

本项目通过分析我国南北方夏季高温模式，研究模拟基于平均温度升高和高温持续日数增加的夏季高温模式对小菜蛾个体和种群统计学的影响。1）模拟了连续世代平均温度升高对小菜蛾存活、成虫繁殖量，以及内禀增长率的影响，以及早期生命阶段经历间歇性高温后南北方不同高温的生态学效应。阐明温度升高将对小菜蛾存活、发育、繁殖，以及内禀增长率产生负面影响。早期生命阶段间歇性高温可以延续到成虫，总繁殖量下降；而后续继续持续中等高温可掩盖早期的高温效应。2）研究模拟了南北方夏季不同持续时间的间歇性高温下的存活，以及对后续成虫命和产卵表现的影响，提出了高温剂量与后续表现的复杂关系。3）调查了南北方夏季小菜蛾田间种群发生规律。连续种植甘蓝下，在南方小菜蛾夏季虫量发生量急剧减少，甚至最热月份数量为0；而在北方整个夏季，小菜蛾种群数量一直居高不下。本项目研究结果对提高气候变化条件下害虫预测水平，制定科学应对气候变化的害虫防治策略具有重要应用价值。本项目所得结论在气候变化生物学和生态学研究方面具有一定的理论和实际意义。