Randolph S E, Rogers D J
Department of Zoology, University of Oxford.
Parasitology. 1997 Sep;115 ( Pt 3):265-79. doi: 10.1017/s0031182097001315.
We present a simulation population model for the African tick Rhipicephalus appendiculatus, based on previous analyses of the mortality factors most closely correlated with observed population changes at 11 sites in equatorial and South Africa. The model incorporates temperature-dependent rates of egg production and development, climate-driven density-independent mortality rates, particularly during the adult-larval stage, and density-dependent regulation of both nymphs and adults. Diapause is also included for tick populations in southern Africa. The model successfully describes both the seasonality and annual range of variation in numbers of each tick stage observed at each of 4 test sites in Uganda, Burundi and South Africa. Sensitivity analysis showed that the final version of the model is robust to 4-fold variation in most parameter values (that were per force based on informed guesses), but is more sensitive to the regression coefficients determining density-dependent interstadial mortality (that were derived from analysis of field data). The model is able to predict the seasonality of ticks from a site in Kenya where a full prior population analysis was not possible because only adults and nymphs had been counted. The model is potentially applicable to other species of ticks, both tropical and temperate, to predict tick abundance and seasonality as risk factors for tick-borne diseases.
我们基于此前对赤道非洲和南非11个地点与观察到的种群变化密切相关的死亡因素的分析，提出了一种非洲蜱——微小扇头蜱的模拟种群模型。该模型纳入了温度依赖的产卵和发育速率、气候驱动的密度独立死亡率（尤其是在成蜱-幼蜱阶段），以及若蜱和成蜱的密度依赖调节。南部非洲的蜱种群还包括滞育情况。该模型成功地描述了在乌干达、布隆迪和南非4个测试地点观察到的每个蜱阶段数量的季节性和年度变化范围。敏感性分析表明，模型的最终版本对大多数参数值（这些参数值最初是基于有根据的猜测）的4倍变化具有稳健性，但对决定密度依赖的不同发育阶段死亡率的回归系数（这些系数来自野外数据分析）更为敏感。该模型能够预测肯尼亚一个地点蜱的季节性，在该地点由于只统计了成蜱和若蜱，之前无法进行完整的种群分析。该模型有可能适用于其他热带和温带蜱种，以预测蜱的丰度和季节性，作为蜱传疾病的风险因素。
