Theory generally predicts that host specialisation and dispersal should evolve jointly. Indeed, many models predict that specialists should be poor dispersers to avoid landing on unsuitable hosts while generalists will have high dispersal abilities. Phytophagous arthropods are an excellent group to test this prediction, given extensive variation in their host range and dispersal abilities. Here, we explore the degree to which the empirical literature on this group is in accordance with theoretical predictions. We first briefly outline the theoretical reasons to expect such a correlation. We then report empirical studies that measured both dispersal and the degree of specialisation in phytophagous arthropods. We find a correlation between dispersal and levels of specialisation in some studies, but with wide variation in this result. We then review theoretical attributes of species and environment that may blur this correlation, namely environmental grain, temporal heterogeneity, habitat selection, genetic architecture, and coevolution between plants and herbivores. We argue that theoretical models fail to account for important aspects, such as phenotypic plasticity and the impact of selective forces stemming from other biotic interactions, on both dispersal and specialisation. Next, we review empirical caveats in the study of this interplay. We find that studies use different measures of both dispersal and specialisation, hampering comparisons. Moreover, several studies do not provide independent measures of these two traits. Finally, variation in these traits may occur at scales that are not being considered. We conclude that this correlation is likely not to be expected from large-scale comparative analyses as it is highly context dependent and should not be considered in isolation from the factors that modulate it, such as environmental scale and heterogeneity, intrinsic traits or biotic interactions. A stronger crosstalk between theoretical and empirical studies is needed to understand better the prevalence and basis of the correlation between dispersal and specialisation.

中文翻译：

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使用植食性节肢动物作为模型组了解传播和宿主专业化的联合进化

理论普遍预测宿主的专业化和扩散应该共同进化。事实上，许多模型预测专家应该是较差的分散者，以避免降落在不合适的宿主上，而通才将具有较高的分散能力。植食性节肢动物是检验这一预测的绝佳群体，因为它们的寄主范围和传播能力存在很大差异。在这里，我们探讨了有关该群体的实证文献与理论预测的一致程度。我们首先简要概述预期这种相关性的理论原因。然后，我们报告了测量植食节肢动物的扩散和专业化程度的实证研究。我们在一些研究中发现分散性和专业化水平之间存在相关性，但这一结果存在很大差异。然后，我们回顾了可能模糊这种相关性的物种和环境的理论属性，即环境颗粒、时间异质性、栖息地选择、遗传结构以及植物和食草动物之间的共同进化。我们认为，理论模型未能解释重要方面，例如表型可塑性以及其他生物相互作用产生的选择力对分散和专业化的影响。接下来，我们回顾一下这种相互作用研究中的经验警告。我们发现研究使用了不同的分散性和专业化衡量标准，阻碍了比较。此外，一些研究没有提供这两个特征的独立测量。最后，这些特征的变化可能会在未考虑的范围内发生。我们的结论是，大规模比较分析可能不会预期这种相关性，因为它高度依赖于环境，不应脱离调节它的因素来考虑，例如环境规模和异质性、内在特征或生物相互作用。为了更好地理解分散和专业化之间相关性的普遍性和基础，需要在理论和实证研究之间进行更强有力的交流。