Data from: Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations

The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. Here, this framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain) and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid 21-century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current predictions based on mean temperature anomalies are relatively conservative and it is better to apply stochastic tools to resolve complex responses to climate change while taking natural variability into account. In summary, we propose here a modeling framework capable of determining distinct intra-annual temperature patterns leading to large or small population sizes, for pest risk assessment and management planning of both natural and agricultural ecosystems.

昆虫的世代周期普遍较短，这使得其种群动态不仅对年平均气温高度敏感，同时也受年内气温波动的显著影响。为考量全球变暖背景下两类热因子的综合效应，本研究提出一套耦合通用环流模式（General Circulation Models，GCMs）、随机天气发生器（stochastic weather generator）与种群动态模型的建模框架，用于预测物种种群对年际及年内气温变化的响应。
本研究利用该框架，针对地中海地区多类农业生态系统均造成危害的入侵性害虫——烟粉虱（Bemisia tabaci）的种群未来变化展开探究。我们选取了代表不同害虫发生态势与气候条件的三个研究区域：法国蒙彼利埃、西班牙塞维利亚以及以色列贝特贾马尔。针对这三个区域，我们基于两种排放情景，生成了代表当前及未来（21世纪中期）气候条件的局地逐日气温集合模拟序列。
模拟结果显示，三个区域的年平均世代数、种群规模均显著提升，且作物生育期显著延长。仅在西班牙塞维利亚的夏季观测到负面影响：未来气温升高将导致该区域种群规模缩减。在年平均气温相近的年份间，种群规模存在显著差异，这表明年内气温波动对种群的影响极强。
蒙彼利埃的种群关键期为晚春至夏末，而塞维利亚与贝特贾马尔的关键期则为晚冬至初夏。尽管本研究分析表明，除非额外多产生一个世代，否则季候活动提前未必会提升种群负荷，但未来50年内，该昆虫极有可能成为地中海纬度40°以上露天农田的主要害虫。
本研究的模拟结果还显示，当前基于气温距平的预测相对保守，在考量自然变异性的前提下，采用随机工具解析气候变化下的复杂种群响应更为适宜。综上，本研究提出的建模框架可用于识别驱动种群规模增减的特有年内气温模式，可为自然与农业生态系统的害虫风险评估及管理规划提供支撑。