International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
PLoS One. 2018 Jun 22;13(6):e0199569. doi: 10.1371/journal.pone.0199569. eCollection 2018.
The antestia bug, Antestiopsis thunbergii (Gmelin 1790) is a major pest of Arabica coffee in Africa. The bug prefers coffee at the highest elevations, contrary to other major pests. The objectives of this study were to describe the relationship between A. thunbergii populations and elevation, to elucidate this relationship using our knowledge of the pest thermal biology and to predict the pest distribution under climate warming. Antestiopsis thunbergii population density was assessed in 24 coffee farms located along a transect delimited across an elevation gradient in the range 1000-1700 m asl, on Mt. Kilimanjaro, Tanzania. Density was assessed for three different climatic seasons, the cool dry season in June 2014 and 2015, the short rainy season in October 2014 and the warm dry season in January 2015. The pest distribution was predicted over the same transect using three risk indices: the establishment risk index (ERI), the generation index (GI) and the activity index (AI). These indices were computed using simulated life table parameters obtained from temperature-dependent development models and temperature data from 1) field records using data loggers deployed over the transect and 2) predictions for year 2055 extracted from AFRICLIM database. The observed population density was the highest during the cool dry season and increased significantly with increasing elevation. For current temperature, the ERI increased with an increase in elevation and was therefore distributed similarly to observed populations, contrary to the other indices. This result suggests that immature stage susceptibility to extreme temperatures was a key factor of population distribution as impacted by elevation. In the future, distribution of the risk indices globally indicated a decrease of the risk at low elevation and an increase of the risk at the highest elevations. Based on these results, we concluded with recommendations to mitigate the risk of A. thunbergii infestation.
安特斯蒂opsis 臭虫（Antestiopsis thunbergii）（Gmelin 1790）是非洲阿拉伯咖啡的主要害虫。与其他主要害虫相反，臭虫更喜欢在海拔最高的咖啡树上取食。本研究的目的是描述 A. thunbergii 种群与海拔的关系，利用我们对害虫热生物学的了解来阐明这种关系，并预测气候变暖下害虫的分布。在坦桑尼亚乞力马扎罗山海拔 1000-1700 米的一个海拔梯度的横切线上的 24 个咖啡农场中，评估了安特斯蒂opsis 臭虫的种群密度。在 2014 年和 2015 年的 6 月凉爽干燥季节、2014 年 10 月的短雨季和 2015 年 1 月的温暖干燥季节评估了三个不同的气候季节的密度。使用三个风险指数：建立风险指数（ERI）、世代指数（GI）和活动指数（AI），在同一横切线上预测了害虫的分布。这些指数是通过使用来自温度相关发育模型的模拟生命表参数和 1）来自现场记录的数据记录器在横切线上的部署以及 2）从 AFRICLIM 数据库中提取的 2055 年预测值计算得到的。观察到的种群密度在凉爽干燥季节最高，并随海拔的升高而显著增加。对于当前的温度，ERI 随着海拔的升高而增加，因此与观察到的种群分布相似，而与其他指数相反。这一结果表明，在海拔高度影响下，种群分布的关键因素是对极端温度的幼期易感性。在未来，风险指数的全球分布表明，低海拔的风险降低，而高海拔的风险增加。基于这些结果，我们提出了减轻 A. thunbergii 感染风险的建议。
