Cuprininae is a small lineage within the moth family Stathmopodidae, characterized by tiny adults and larvae that feed exclusively on fern spores. This feeding habit is rare not only among butterflies and moths but among insects generally. A recent evolutionary analysis suggested that fern-spore feeding probably evolved once within Stathmopodidae and has been reported in Cuprininae and two other genera, Agrioscelis and Erineda. Cuprininae is not restricted to a single fern genus or family: larvae have been recorded from at least 11 fern families, indicating a broader but still specialized form of host use described as oligophagy.

Before this study, three Cuprininae species had been reliably recorded in Korea: Calicotis chrysoptera, C. latebrifica and Cuprina fuscella. The researchers examined material representing C. latebrifica and C. fuscella, the two previously recorded species included in their morphological and molecular comparisons, alongside the two newly described species and three new country records. C. chrysoptera was not examined in the study. Pachyrhabda benearena, recently described from Korea, was also excluded from the confirmed Cuprininae list because its taxonomic placement requires further examination.

The newly described Pediformis astathmeta is the third species recognized in its genus and can be separated from its two congeners by details of the male genitalia. Its cucullus, the foot-shaped apical portion of the valva, narrows gradually toward a rounded apex; the cucullus of P. cuneiformis is rectangular, whereas that of P. fushana ends in a pointed projection. The aedeagus of P. astathmeta is much narrower and longer than those of the other two species. Females have two signa, and the signum nearest the ductus bursae is smaller and rounder than in P. cuneiformis. The moth has a forewing span of 8.0–10.0 mm across 31 specimens, with pale wings and indistinct grey markings.

Field and laboratory observations also documented the biology of P. astathmeta. Its larvae were found feeding beneath fronds of the fern Arachniodes sporadosora, where they made tunnel-like shelters and silky galleries before forming cocoons. Adults flew in May, while larvae were observed only in June, a seasonal pattern suggesting that the species is probably univoltine, or has one generation per year. The moth shared a habitat with C. fuscella, and both occurred on A. sporadosora. However, P. astathmeta larvae were found only on that fern, whereas C. fuscella larvae consumed A. sporadosora and three additional fern species in the family Dryopteridaceae.

The second new species, Calicotis atricosta, is distinguished by a whitish forewing with a black basal section of the costa and a broad, inwardly oblique black band before the wing midpoint. Unlike many related species, it lacks dark blotches or streaks in the distal part of the forewing. Its male genitalia supply further diagnostic traits, including an oval cucullus, an oval anellar lobe and a rounded juxta. The aedeagus bears a narrow apical spatulate projection about one-third of its length. The name atricosta refers to the black basal costa. Only two male specimens were available, so no female genitalia, wing-venation slide, host plant or life-history information could be established for C. atricosta.

The first Korean record of Cuprina porphyrantha is difficult to distinguish from C. fuscella by superficial appearance, because both have dark forewings without distinct markings. Antennal coloration provides one useful difference: the scape of C. porphyrantha is ochreous-yellow dorsally, compared with fuscous to dark grey in C. fuscella, and the apical portion of its antenna is more broadly pale, although that feature can sometimes be indistinct. The basal sclerotized portion of the aedeagus is also larger in C. porphyrantha. A Korean larva was found on Arachniodes aristata, while an adult was collected in August. The species has also been reported from Japan, Russia, Sri Lanka and Taiwan.

The two newly recorded Petala species can likewise be separated through a combination of external and genital characters. Petala aedificatrix has a measured forewing span of 10.0 mm, compared with 6.5–7.5 mm for the 12 examined P. margaritacea specimens, and its forewing markings are less distinct. It also bears black bristles at the apex of the hind tibia rather than the white to pale-grey bristles of P. margaritacea. In the male genitalia, the cucullus of P. aedificatrix curves outward apically and the sacculus is indistinct; P. margaritacea has an uncurved cucullus and a sacculus with a rounded apex. The aedeagus of P. aedificatrix has a distinctive needle-like cornutus with a sharply pointed apex.

To test the classifications, the team extracted DNA from one or two legs of dried adults and from larvae, then analyzed the mitochondrial protein-coding gene cytochrome c oxidase subunit I together with four nuclear genes: EF-1α, carbamoyl-phosphate synthase domain, histone H3 and wingless. The concatenated alignment was 2,578 base pairs long and included sequences representing 37 additional Cuprininae species and the stathmopodid outgroup Stathmopoda auriferella. Maximum-likelihood and Bayesian analyses produced largely congruent trees, placing all seven Korean taxa in their respective genera. P. astathmeta occurred within a strongly supported Pediformis clade, with an ultrafast bootstrap value of 96 and a Bayesian posterior probability of 1, while C. atricosta joined Calicotis with bootstrap support of 100 and posterior probability of 1.

The molecular results also supported the species-level identities of the three new Korean records. Petala aedificatrix, P. margaritacea and Cuprina porphyrantha grouped with previously identified sequences from the same species in other regions, providing an independent line of evidence for their placement. Confidence is lower for some deeper relationships within Cuprininae. Both analyses placed Calicotis and Cuprina as sister lineages, with Trigonoda outside that pair, but the bootstrap support was moderate and this topology differed from one analysis in an earlier family-level study. The present dataset focused on Cuprininae and verification of Korean taxa, and several nuclear genes were missing for some specimens, so broader sampling is needed to clarify the subfamily’s deeper evolutionary relationships.

Subject of Research: Taxonomic and molecular study of seven Cuprininae moth species collected on Jeju Island, South Korea

Article Title: Two new species and three new records of Cuprininae ( Lepidoptera , Stathmopodidae ) from Jeju Island, Korea, with molecular evidence for their placement

Article References: Lee, G.-E., & Terada, T. (2026). Two new species and three new records of Cuprininae (Lepidoptera, Stathmopodidae) from Jeju Island, Korea, with molecular evidence for their placement. ZooKeys, 1287, 253-272. https://doi.org/10.3897/zookeys.1287.194473

Image Credits: AI Generated

DOI: 10.3897/zookeys.1287.194473

Keywords: Cuprininae, Stathmopodidae, moth taxonomy, new species, Jeju Island, phylogenetics, fern-spore feeding, Korean fauna, DNA barcoding, species records, species, three