Experimental Analysis of the Dynamic Effects of a Refuge

本研究旨在确定物理避难所对捕食-猎物系统动力学的影响。红鳞是美国加州南部柑橘类害虫，主要由拟寄生性葡萄球菌控制。在柑橘树的内部，有一定规模的避难种群，在一定程度上因品种而异。柑橘品种在其外部叶子和果实上的鳞片负荷也各不相同。待验证的假设是，树叶上鳞片密度稳定的关键是避难所种群的发展程度。将对柑橘林进行广泛的调查，以检验这一假设，其中将对避难所和外部种群进行抽样。将进行一系列的实验，旨在为天敌死亡率和爬行动物迁移率的品种间差异提供机制解释。利用这些信息，将开发一个预测避难所人口对外部人口影响的模型。红鳞-葡萄球菌相互作用被认为是研究物理避难所对种群动态影响的模型系统。将评估该避难所对人口规模的影响，并将量化决定该避难所对总征聘人数的贡献的因素。

This research is aimed at determining the consequences of a physical refuge upon the dynamics of a predator-prey system. Red scale is pest of citrus that is controlled by the parasitoid Aphytis in southern California. A refuge population of scale exists, to an extent that varies among cultivars, in the interior of the citrus tree. Citrus cultivars also vary in the scale load they carry on exterior foliage and fruit. The hypothesis to be tested is that a key to the stability of scale density on the foliage is the extent to which the refuge population is developed. An extensive survey of citrus groves will be conducted to test this hypotheses in which both the refuge and exterior populations will be sampled. A series of experiments aimed at providing a mechanistic explanation for between-cultivar variation in terms of mortality due to natural enemies and crawler migration rates will be done. Using this information, a model that predicts the influence of refuge populations on exterior populations will be developed. Red scale-Aphytis interaction is considered a model system for studying the effect of a physical refuge on population dynamics. The impact of the refuge in terms of effect on population size will be assessed and the factors determining the contribution of the refuge to total recruitment will be quantified.