Introduction
The subfamily Thelaxinae (Hemiptera, Aphididae) is a small group comprising four genera and 21 valid species worldwide (Favret 2026). The genus Kurisakia Takahashi, 1924 currently comprises seven valid species (Favret 2026). Species of Kurisakia are associated primarily with woody plants of Fagaceae and Juglandaceae, although information on their sexual morphs and life cycles remains limited for most species (Favret and Aphid Taxon Community 2026).
Kurisakia querciphila Takahashi, 1960 was originally described from Japan as Kurisakia onigurumii querciphila, based on specimens collected from Quercus acutissima (Takahashi 1960) and was subsequently treated as a distinct species (Zhang and Zhong 1979). In Korea, Paik recorded K. onigurumii from Q. acutissima and Castanea crenata (Paik 1965), but this record was later referred to K. querciphila by Favret and Aphid Taxon Community (2026). Nevertheless, the current National Species List of Korea lists only K. onigurumii within Kurisakia, whereas K. querciphila is not included (National Institute of Biological Resources 2019). Thus, the taxonomic treatment of Kurisakia in the Korean fauna warrants clarification and updating.
Detailed morphological information and illustrations of K. querciphila, based on Korean specimens remain limited. In the present study, we re-describe and illustrate the apterous viviparous female, based on recently collected specimens and document its host plant and geographic distribution. The COI sequence obtained from a single individual was deposited in GenBank. Our results confirm the occurrence of K. querciphila in South Korea, based on morphologically identified specimens and provide a taxonomic basis for updating the National Species List of Korea.
Materials and methods
Sampling and morphological identification
Colonies of K. querciphila Takahashi, 1960 were collected from the undersides of the young leaves of Quercus variabilis in Gajwa-dong, Jinju-si, Gyeongsangnam-do, South Korea (35°09'38.47"N 128°05'46.42"E) in 2024. The samples were preserved in 95% alcohol and mounted in Canada balsam on glass slides, following published procedures (Blackman and Eastop 2000). Slide-mounted specimens were examined using a Leica DM3000 LED light microscope and identified as Kurisakia querciphila by comparison with the original description (Takahashi 1960). All specimens were deposited in the Institute of Agriculture & Life Science, Gyeongsang National University, South Korea. The following abbreviations are used in morphological features: BL, body length from the head to the end of cauda; Ant., antennae; Ant.I–Ⅴ and Ant.Ⅴb, antennal segments I–Ⅴ and basal part of antennal segment Ⅴ, respectively; PT, processus terminalis; BDAnt.III, basal diameter of antennal segment III; Setae on Ant.Ⅲ, the longest seta on antennal segment III; 2HT, second segment of hind tarsus; HFM, hind femur; HTB, hind tibia; SIPH, siphunculus; Cauda BW, basal width of cauda; and URS, ultimate rostral segment. Siphuncular measurements are expressed as diameters.
DNA extraction, amplification, sequence alignment and data analyses
Total genomic DNA was extracted from a single apterous viviparous female using the AccuPrep® Genomic DNA Extraction Kit (Bioneer, Daejeon, South Korea), following the manufacturer’s protocol. The DNA fragments were amplified using AccuPower® PCR PreMix (Bioneer, Daejeon, South Korea). The partial sequence of the mitochondrial COI gene was amplified using the primer pair LCO1490 (5’–GGT CAA CAA ATC ATA AAG ATA TTG G–3’) and HCO2198 (5’–TAA ACT TCA GGG TGA CCA AAA AAT CA–3’) (Folmer et al. 1994). We used the following thermal cycle parameters for a 20 μl amplification reaction: an initial denaturation for 5 min at 94°C, followed by 34 cycles of 1 min at 94°C, 1 min at 48°C and 1 min at 72°C and a final extension at 72°C for 5 min. The PCR product was tested by electrophoresis on 1.5% agarose gel and, if a single band was observed, we commissioned Bionics (Seoul, Korea) for purification and sequencing analysis. The sequence was assembled using SeqMan (version 7.0.1, DNASTAR Inc.) and alignment was performed using MEGA version 12 (Kumar et al. 2024). The COI sequence generated in this study has been deposited in GenBank under accession number PZ336710.