B型烟粉虱对23种寄主植物适应度的评估和聚类分析

本文利用前期开发的两个寄主植物适应度评估模型对B型烟粉虱能够完成发育的23种寄主进行了寄主适应度评估，并对评估结果进行了聚类分析，分析结果显示供试烟粉虱种群存在明显的寄主偏好性，黄瓜与甘蓝为嗜好寄主，繁殖力大，若虫成活率高，非常有利于烟粉虱的种群发育；而其它寄主在营养状况、物理性状及次生化合物的综合作用下，烟粉虱的寄主植物适应度变化较大且整体低于嗜好寄主，结果暗示烟粉虱的寄主生态位可能存在从核心到周缘的分层现象。比较了两个评估模型的分析结果，虽然在低层聚类中存在差异，但高层聚类的结果趋于一致。

Performance evaluation of B biotype whitefly, Bemisia tabaci on 23 host plants

The B biotype of whitefly Bemisia tabaci has been regarded as an extreme generalist capable of causing heavy damage to many vegetables, ornamental plants and other crops. However, field and laboratory observations show that whitefly populations vary greatly in their performance on different host plants. A combination of factors including secondary chemicals, physical features and nutrition likely explain performance variations for herbivores feeding on different host plants, but the real situation might be even more complex than expected. In this study, the fecundity and survivorship of B biotype whitefly reared on 29 plant species were measured. Then fitness of whitefly on each host plants was estimated using two models that were designed to assess larval performance for herbivore populations. The fitness data for 23 plant species were analyzed by statistical methods that classified all hosts into 2 groups: preferred and acceptable. The preferred host group included only cucumber and cabbage on which whitefly performed very well with high fecundity and survivorship. In contrast, the acceptable host group included the remaining host plants where whitefly showed varied and modest nymphal performance. B biotype whitefly populations might depend on a hierarchy of niches as a means for adapting to host plants and exploiting new habitats. Whitefly are likely to occupy nuclear niches on several preferred plants that are important for population increase or shelter during unfavorable periods or in suboptimal environments. Meanwhile a wide range of acceptable hosts permit whitefly populations to spread and invade new areas around the world. It is still unclear why some whitefly biotypes (B and Q) were able to develop more successful niches than others. So future research should examine additional niche features such as structure and scale, source and sink potential, especially for generalist invasive species.