The effects of toxicants, such as pesticides, may be more severe for some life stages of an organism than others. However, in most toxicity studies, data is developed for only one life stage, which may lead to misleading interpretations. Furthermore, population stage-structure may interact with differential susceptibility, especially when populations consist of higher proportions of individuals in more susceptible stages at the time of toxicant exposure. We explore the interaction of differential stage susceptibility and stage distribution using a stage-structured Lefkovitch matrix model. We incorporate lab-derived toxicity data for a common parasitoid, the braconid Diaeretiella rapae (M’Intosh), a common natural enemy of the cabbage aphid (Brevicoryne brassicae L.), exposed to the pesticide imidacloprid. We compare population outcomes of simulations in which we vary both the population stage structure along with the susceptibility of each stage to toxicants. Our results illustrate an interaction between differential susceptibility and initial stage distribution, highlighting the fact that both of these demographic features should be considered in interpreting toxicity data and the development of ecological risk assessments.

在有机体的某些生命阶段中，诸如农药之类的有毒物质的影响可能比其他生物更为严重。但是，在大多数毒性研究中，仅针对一个生命阶段开发数据，这可能导致误解。此外，人群的阶段结构可能会与不同的易感性相互作用，特别是当人群在暴露有毒物质时，在较高的易感阶段中由较高比例的个体组成时。我们使用阶段结构的Lefkovitch矩阵模型探索微分阶段敏感性和阶段分布的相互作用。我们实验室一体化源性毒性数据为共同的寄生蜂，在茧蚜茧蜂（M'Intosh），甘蓝蚜的共同天敌（甘蓝蚜L.），暴露于吡虫啉杀虫剂。我们比较了模拟的人口结果，在模拟中，我们改变了人口阶段结构以及每个阶段对毒物的敏感性。我们的结果说明了差异敏感性和初始阶段分布之间的相互作用，强调了以下事实：在解释毒性数据和开发生态风险评估时，应同时考虑这两个人口特征。