Calaphidinae is one of the most species rich group in Aphididae. However their phylogenetic relationship is poorly understood. In this study, we reconstructed phylogenetic relationship of Calaphidinae and closely related groups to confirm the taxon boundary and ingroup relationship such as tribe and genera. In addition, evolutionary hypothesis of ancestral host-plant relationship was tested. We performed Bayesian inference and maximum likelihood analyses of combined 4 mitochondrial (ATP6, COI, COII, CytB) and 1 nuclear (EF1α) sequences. Phylogenetic results suggested that Calaphidinae is not a monophyletic and Saltusaphidinae is nested in Calaphidinae. Phyllaphidinae forms a basal clade as the most primitive group of Calaphidinae. Reconstruction of ancestral host plant of Calaphidinae indicated that Calaphidinae might have evolved on members of Fagales plants.

Generally, in aphid groups, taxonomically deficient characters and high level of morphological plasticity induced by environmental factors make difficulties for species identification. To solve these problems, DNA barcoding has been widely used for rapid and reliable species identification in aphids. The subfamily Calaphidinae is the second largest group in the family Aphididae with about 400 species belong to 59 genera. But so far, no trial of DNA barcoding has been conducted for the subfamily Calaphidinae. In this study, a total of 446 Cytochrome oxidase I (COI) sequences of 76 morphospecies collected in Korea and other countries were analyzed to detect cryptic diversity. In addition, 551 sequences of 74 species from the Genbank and BOLD system were compared with our new dataset. The final dataset consisted of 998 sequences of 115 species. As a results, we propose 12 cryptic species with discussion on morphological and ecological comparisons. Our results suggest that DNA barcoding is effective for precise species identification in this group and contributes to reveal hidden diversity.

The subgenus Nippocallis (Matsumura, 1917) is one of the 10 subgenera of the genus Tuberculatus Mordvilko, 1894. Originally, this subgenus was regarded as an independent genus of the subtribe Myzocallidina by the distinct morphological features and the host plant association with Castanea (Fagaceae). We performed molecular and morphological analyses to determine whether genus Nippocallis belongs to Tuberculatus group. Molecular analysis of the combined data set of Cytochrome Oxidase subunit I COI, Cytochrome B CytB and Elongation Factor I-alpha EF1α indicated that Nippocallis form a sister clade of the genus Myzocallis Passerini, 1860, apart from the genus Tuberculatus. In this contexts, we propose Nippocallis as a separate genus of the subtribe Myzocallidina.

On Birches (Betula spp.), more than seventy species of aphids in eighteen genera are recorded worldwide, mostly (> 60%) belonging to ten genera of the subfamily Calaphidinae (Hemiptera: Aphididae). In Korea, only seven Birch feeding aphids are recorded. Recently, we recognized two calaphinid species, Calaphis betulaecolens (Fitch, 1851) and Euceraphis betulae (Koch, 1855) as new to the Korean peninsula.