Phylogeographic patterns in phytophagous organisms are often contextualized in light of geographic isolation and ecological (host, habitat) specialization. However, assessing the relative impact of these phenomena is not straightforward, even in areas where phylogeography is well-studied, such as the California Floristic Province. Here, we use genome-wide markers to elucidate population genomic and phylgeographic patterns for a group of monophytophagous butterflies in southern California. This group is of high conservation interest because it includes the El Segundo blue, Euphilotes battoides allyni, one of the first insects listed under the U.S. Endangered Species Act, and a newly discovered population putatively assigned to E. b. allyni. Despite using the same unique host and coastal habitat, our results indicate that the newly discovered populations are not E. b. allyni and are more closely related to geographically proximate populations of the E. battoides group using a different habitat/host combination. Aside from E. b. allyni and the newly discovered populations, the rest of the group shows only fine-scale structure and apparently maintains genetic connectivity throughout southern California, across a vast range of habitats and climates, and on multiple hosts. Thus, habitat and host specialization did not elicit genetic isolation in neighboring populations suggesting that: (1) other phenomena are needed to explain the remarkable and idiosyncratic divergence of these highly restricted, proximate, taxa, and (2) fine-scale genomic markers suggest broader implications for understanding the mechanisms of speciation and reinvestigation of phylogeographic patterns in regions like the California Floristic Province.

根据地理隔离和生态学（寄主，生境）的专业化，通常将植物噬菌体中的植物志模式化。但是，评估这些现象的相对影响并不是一件容易的事，即使是在对植物地理学进行了深入研究的地区，例如加利福尼亚植物区系。在这里，我们使用全基因组标记物阐明了加利福尼亚南部一群单食性蝴蝶的种群基因组和系统发育模式。该组具有很高的保护意义，因为它包括El Segundo蓝，Euphilotes battoides allyni，美国《濒危物种法》列出的首批昆虫之一以及新发现的推定为E. b的种群。艾莉妮。尽管使用了相同的独特寄主和沿海生境，但我们的结果表明，新发现的种群并非大肠杆菌。allyni，并且使用不同的栖息地/寄主组合，与蝙蝠大肠杆菌组的地理上更接近的种群有更紧密的联系。除了E. b。艾莉妮和新发现的种群，该小组的其余成员仅表现出精细的结构，并且显然在整个加利福尼亚南部，范围广泛的生境和气候以及多个寄主上保持了遗传连通性。因此，栖息地和寄主的专业化并未引发邻近人群的遗传隔离，这表明：（1）还需要其他现象来解释这些高度受限的，近缘的，分类群的显着和特异的差异，以及（2）精细的基因组标记对于了解加利福尼亚植物区系等地区的物种学特征和物种学模式进行再研究的机制具有更广泛的意义。