Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of Nevada, Reno, Nevada 89557, USA.
Evolution. 2011 Sep;65(9):2719-24. doi: 10.1111/j.1558-5646.2011.01310.x. Epub 2011 Apr 22.
The study of host shifts by herbivorous insects has played an important role in evolutionary biology, contributing to research in coevolution, ecological speciation, and adaptive radiation. As invasive plants become more abundant in many ecosystems, the potential for exotic host use by native insects increases. Graves and Shapiro (2003) have documented exotic host use by 34% of Californian butterflies, suggesting that the plants and butterflies of California might be an important model system for the colonization and utilization of novel resources. In this study, we analyze relationships among geographic range, native diet breadth, and the use of exotic hosts by Californian butterflies and skippers (Lepidoptera). Geographic range and, to a lesser extent, native diet breadth are significant predictors of exotic host use, with positive relationships found both before and after phylogenetic correction. These results give insight into the process of insect host range evolution, as geographically widespread generalists have an apparently greater tendency to use novel, exotic hosts than geographically constrained specialists. Increasing occurrences of exotic host use are expected and those species not capable of shifting to nonnative hosts are likely to have higher vulnerability to extirpation and extinction in the future.
植食性昆虫的寄主转移研究在进化生物学中发挥了重要作用，为共同进化、生态物种形成和适应性辐射的研究做出了贡献。随着入侵植物在许多生态系统中变得更加丰富，本地昆虫利用外来寄主的潜力也在增加。Graves 和 Shapiro（2003 年）记录了加利福尼亚蝴蝶中有 34%利用了外来寄主，这表明加利福尼亚的植物和蝴蝶可能是一个重要的模型系统，用于研究外来资源的殖民和利用。在这项研究中，我们分析了加利福尼亚蝴蝶和弄蝶（鳞翅目）的地理分布范围、本地饮食广度以及利用外来寄主之间的关系。地理分布范围和在较小程度上本地饮食广度是利用外来寄主的重要预测因子，在进行系统发育校正之前和之后都发现了正相关关系。这些结果深入了解了昆虫寄主范围进化的过程，因为地理分布广泛的广食性通常比地理上受限制的特化种更倾向于利用新的、外来的寄主。预计外来寄主的利用会越来越多，那些不能转移到非本地寄主的物种在未来可能更容易灭绝。
