Host-shifting pattern common in relatives: phylogenetic study of Sapindaceae-associated <i>Cameraria</i> (Lepidoptera: Gracillariidae), with a description and population genetics of <i>Cameraria serena</i> sp. nov.

Abstract Host shifting is a key driver of diversification in phytophagous insects, and multiple host shifts between the same host pairs within a single insect taxon may be one factor in their greater species richness compared to plants. The leaf-mining moth genus Cameraria (Lepidoptera: Gracillariidae) contains several Acer-feeding and Aesculus-feeding species, and their morphology implies multiple host shifts between Acer and Aesculus. We inferred phylogenetic relationships among these Cameraria species based on multilocus data, indicating that such host shifts occurred once in the Nearctic and twice in the Palearctic. We describeCameraria serena sp. nov., a Japanese Aesculus turbinata-feeder, which is sister to C. acericola, an East Asian Acer-feeder, rather than to European or North American Aesculus-feeders. Population genetic analyses revealed two genetic groups within C. serena, exhibiting different historical population dynamics but with almost completely overlapping current geographical distributions. Despite its strict host association, C. serena shows a phylogeographical structure incongruent with that of its host (Aesculus turbinata). This discrepancy, in light of the multiple shifting events inferred from the phylogenetic analysis, probably reflects delayed colonization of Aesculus turbinata by C. serena as well as differences between their dispersal abilities.