The geographic mosaic model of plant–herbivore coevolution asserts that interactions between a plant species and an herbivore species vary in intensity among populations across the plant’s geographic range. Despite this model’s intuitive appeal, data to investigate its implications for the type of complex, multiple-herbivore communities that occur in nature are scant. This paper reports on the results of 2 years of field surveys of damage by five leaf herbivores and one stem herbivore in four Solanum carolinense (horsenettle) populations, combined with results of a common-garden study quantifying the mean resistance levels of the plants from each field against each of the six herbivores. The relative amounts of damage caused by each species (representing the “herbivore-community structure”) differed significantly among the four fields. The plants were much more heavily damaged in the 2nd year than in the first, but the herbivore-community structure remained stable within each field between years. Overall, the amount of damage by species of herbivores in a field tended to be positively correlated with the plants’ levels of resistance that were measured in the common garden (r = 0.40, P = 0.05). Specifically, for five of the six herbivores, greater damage in the field was associated with greater plant resistance. This result suggests that horsenettle’s evolution of resistance against specific herbivores can occur rather quickly within fields, creating a local-scale mosaic of populations specifically adapted to the particular structure of the herbivore community that they are facing, but that herbivore-community structure is not strongly determined by plant resistance.

植物与食草动物共同进化的地理镶嵌模型断言，植物物种和食草动物物种之间的相互作用在植物地理范围内的种群之间强度有所不同。尽管该模型具有直观的吸引力，但用于研究其对自然界中复杂的多食草动物群落类型的影响的数据却很少。本文报告了对四个Solanum carolinense (horsenettle) 种群中五种叶食草动物和一种茎食草动物的损害进行了 2 年实地调查的结果，并结合了一项普通花园研究的结果，该研究量化了每种植物的平均抗性水平场对抗六种食草动物。每个物种（代表“草食动物群落结构”）造成的相对损害量在四个领域之间存在显着差异。第二年植物受到的损害比第一年严重得多，但每一年之间每个田地内的食草动物群落结构保持稳定。总体而言，田间食草动物物种造成的损害程度往往与普通花园中测量的植物抵抗力水平呈正相关（r  = 0.40，P  = 0.05）。具体来说，对于六种食草动物中的五种来说，田间更大的损害与更强的植物抗性有关。这一结果表明，荨麻对特定食草动物的抵抗力的进化可以在田地内相当快地发生，形成一个局部规模的马赛克种群，特别适应它们所面临的食草动物群落的特定结构，但食草动物群落结构并不强烈由植物的抗性决定。