A new species of the genus Donacia Fabricius (Coleoptera, Chrysomelidae, Donaciinae) from South Korea: morphology, ecology, and COI gene analysis Author Kim, Joong Youb https://orcid.org/0009-0008-2271-3104 Research Center for Endangered Species, National Institute of Ecology, Yeongyang, Republic of Korea Author Han, Yeong-Deok 0000-0002-6625-8966 Research Center for Endangered Species, National Institute of Ecology, Yeongyang, Republic of Korea Author Lee, Jong Eun 0000-0003-0536-0032 Department of Biological Science, Gyeongkuk National University, Andong, Republic of Korea text ZooKeys 2025 2025-11-21 1261 83 99 journal article 313193 10.3897/zookeys.1261.169034 b8a59497-3966-43d3-9c07-ed9c820925f8 F7B1C36F-58E6-41EF-A82C-DAC2DD6392BC Donacia koreana Kim & Lee sp. nov. Figs 1 , 2 , 3 , 4 Type locality. South Korea , Kangwon State , Hyeoncheon-ri , Dunnae-myeon , Hoengseong-gun , swamp , 37°30'9.37"N , 128°9'53.57"E . Type materials. Holotype ( NIBR no. NIBRIN 0001069714 ): male , South Korea • Kangwon State , Hyeoncheon-ri , Dunnae-myeon , Hoengseong-gun , swamp , 37°30'9.37"N , 128°9'53.57"E , 520 m , 29. V. 2022 , J. Y. Kim . Paratypes ( NIBR no. NIBRIN 0001069715 ): • five males and seven females , same data as the holotype, except for 6. VI. 2023 , J. Y. Kim . Other materials. Twenty larvae were collected from the roots of Scirpus wichurae Boeckeler with the same data as for the paratype , except for 6.VI.2023 . Diagnosis, adult (Figs 1, 2, 4). The new species closely resembles Donacia bicolora Zschach , but can be distinguished by the following diagnostic characteristics: the rows of punctures are still clearly visible even in the last third of the elytra ( D. bicolora : these punctures are almost completely obscured by the silky, shiny, fine wrinkles in the last third of the elytra).; and it generally occurs in two distinct color morphs: cupreous and greenish ( D. bicolora exhibits a variety of body colorations, commonly greenish, bluish, or blackish). The legs are entirely metallic. Figure 1. Donacia koreana sp. nov. A, B. Male ( A. Holotype); C, D. Female ( C. Paratype). Scale bars: 1.0 mm ( A – D ). Figure 2. Adult: Donacia koreana sp. nov. A. Leg (l. v.); B, C. Pygidium (d. v.); D, E. Abdomen (d. v.); F. Antenna (d. v.); G. Median lobe (l. v.); H. Apex of median lobe (d. v.); I. A cap of tegmen; J, K. Endophallus (d. v. and v. v.); L. Spermatheca. male: A, B, D, F – K ; female: C, E, L. Scale bar: 1.0 mm ( A, D, E, F ); 0.5 mm ( B, C, G, H ); 0.2 mm ( I – L ). Description, adult (Figs 1, 2, 4). Male. Length 7.9–8.1 mm , width 2.7–2.8 mm . Body narrowly elongate; generally cupreous or greenish; head cupreous or greenish; antennomeres 1–4 coppery or greenish, 5 partially darkened, 6–11 dark; pronotum cupreous or greenish; legs cupreous or greenish. Head . Narrower than prothorax; eyes small and convex; supraocular furrow present but shallow; vertex slightly swollen, pubescent with a fine median line. Antenna filiform and pubescent; antennomere 5 longest amongst 2 nd to 6 th ; antennomere 4 slightly longer than 3 rd ; antennomere 5 2.5 times longer than 2 nd . Pronotum . Generally quadrate, width as long as length, posterior and anterior corners prominent; anterolateral calli present, callosal sulcus present but shallow; median line deep; disc coarsely punctate and transverse deep rugae; basal sulcus present but shallow, coarsely punctate. Scutellum . Subtriangular, closely covered with silvery pubescent. Elytron . Subparallel-sided, gradually narrowed apically; surface distinctly 10 longitudinal regular striate, striae regular and deeply punctate; with a shallow depression at the base near the suture (1 st – 4 th sutural intervals), and a deep depression at the base of the median area (5 th – 8 th sutural intervals); apex truncate, outer apical angle obtusely rounded, inner apical angle obtuse. Legs . Slender; metafemur robust in shape, tapering and not distinctly clavate, with a prominent large tooth. Pygidium . Trapezoidal and apex pubescent, emarginate in both sexes. Male genitalia . Median lob of genitalia narrowed apically with median lip and both sides emarginate subapically; a cap of tegmen slender, apex with shallow depression; endophallus elongate, median process short and curving dorsal, BSB elongate. Sterna . Entirely greenish and pubescent; apical shape of last sternite truncate. Female. Length 9.0– 9.3 mm , width 2.8–3.1 mm . Body larger than that of males; pronotum frontal outline quadrate, width longer than length; apical shape of last sternite pointed. Spermatheca . Short and broad, strongly C-shaped; apex tapered; collum and ramus distinct; cornu and nodulus fused into a globose basal swelling; horns widely separated. Description, first instar larva. Length 1.66–1.78 mm , width 0.40–0.41 mm , spiracle-hook length ( 0.213 mm ), and spiracle-hook width ( 0.033 mm ( n = 4). Creamy white, body slightly convex, thorax and abdomen with numerous setae, but not as setae as the last instar larva; egg buster absent. Diagnosis, last instar larva (Figs 3, 4 C). The last instar larva is easily distinguished from the other Donacia larvae by the following characteristics: epicranium with six pairs of dorsal setae; two pairs of sensilla; labrum with three pairs of labral setae and one pair of sensilla; and prementum with one pair of setae and two pairs of sensilla. Figure 3. Larva: Donacia koreana sp. nov. A. Last instar larva (l. v.); B. Antenna (d. v.); C. Head (d. v.); D. Clypeus, labrum and epipharynx (d. v. and v. v.); E. Mandible (b. v.); F. Spiracle (d. v.); G. Maxilla and labium; H. Leg (v. v.); I. 8 th abdominal spiracle. Scale bar: 1.0 mm ( A ); 0.5 mm ( C, H, G, I ); 0.1 mm ( B, E, F ). Figure 4. Donacia koreana sp. nov. A, B. Adults; C. Larva; D. Pupal case; ( C, D red circle). Description, last instar larva (Figs 3, 4 C). Length 10.5–12.3 mm , width 3.7–4.3 mm , head length 0.78–0.84 mm , spiracle hook length 0.73–0.77 mm , spiracle hook width 0.42–0.44 mm ( n = 5). Body yellowish, slightly convex, and C-shaped. Head, prothorax, and legs pale brown; setae and spiracles brown. Head . Prognathous, small, rounded, well sclerotized, strongly retractile into prothorax; hind corner of epicranium slightly posteriorly produced. Epicranial suture Y-shaped; frontal suture nearly straight. Stemmata pigmented, five in number. Epicranium with six pairs of dorsal setae, two pairs of sensilla, and three pairs of lateral setae. Frons with four pairs of frontal setae and one pair of sensilla. Antenna three-segmented: segment 1 with two sensilla, segment 2 with conical sensory papilla and two sensilla basiconica, and segment 3 with two sensilla basiconica and one seta. Endocarina absent; epistomal sutures distinct. Clypeus with two pairs of clypeal setae and one pair of sensilla. Labrum slightly notched anterior margin with three pairs of labral setae and one pair of sensilla. Epipharynx with two pairs of spiniform setae. Mandible conical, strongly sclerotized, with two teeth, 2 nd serrated, and one mandibular seta. Maxillar palp three-segmented; palpifer with two setae; stipes, two setae and one sensillum; galea fused with lacinia, spear-like; cardo large, trapeziform, with one seta. Labial palp one-segmented with one sensillum; ligula with numerous setae; prementum with one pair of setae and two pairs of sensilla; postmentum with two pairs of setae and one pair of sensilla. Thorax . Pronotum pale brown, slightly sclerotized, with numerous setae. Meso-and metanotas not sclerotized. Thoracic spiracles annuliform, situated on the EPa; spiracular opening rounded. Legs short and stout; femur with ten setae and four sensilla; tibio-tarsus with three setae; claws slightly curved, awl-shaped, based enlarged, with one seta; pulvillus absent. Abdomen . Nine segmented, unsclerotized. Typical abdominal segments with two folds. Abdominal spiracles present on segments 1–8 similar to mesothoracic spiracles except for 8 th spiracle. Spiracle hook length about 2.3 times as long as width; projected, large, peg-like, strongly sclerotized. Distribution. South Korea . Host plants. Cyperaceae : Scirpus wichurae Boeckeler , Eleocharis ussuriensis G. Zinserl.

1	Entire dorsum of the beetle not really metallic at all; appendages predominantly bicolored to rufescent; pronotal disc with at most fine punctures and rugulae; elytra with at most few fine rugulae and minute punctulae in intervals	2
–	Entire dorsum of beetle metallic; appendages predominantly dark; pronotal disc coarsely punctured and often transversely coarsely rugose; elytral disc generally coarsely rugose between striae	3
2	Third antennal segment slightly longer than, or as long as second	D. lenzi Schönfeldt
–	Third antennal segment much longer than second	D. provostii Fairmaire
3	Femora and tibia entirely metallic-colored	4
–	Femora and tibia partly metallic-colored (femoral base usually rufous)	5
4	Elytron with red longitudinal stripe	D. aquatica (Linnaeus)
–	Elytron without red longitudinal stripe	6
5	Pronotal disc with distinct fine tum with short hairs (most specimens)	D. clavareaui Jacobson
–	Pronotal disc without distinct short hairs	D. bicoloricornis Chen
6	Body and legs entirely black, unicolored	D. flemola Goecke
–	Body and legs entirely cupreous or green	D. koreana sp. nov.

1	Head inside the prothorax	2
–	Head outside the prothorax	D. flemola Goecke
2	Hind corners of epicranium moderately produced	3
–	Hind corners of epicranium slightly produced	4
3	Ephipharynx with three pairs of spiniform setae	D. clavareaui Jacobson
–	Epipharynx with two pairs of spiniform setae	D. koreana sp. nov.
4	Head ovoid	5
–	Head rounded	6
5	Postmentum with two pairs of setae	D. lenzi Schönfeldt
–	Postmentum with three pairs of setae	D. aquatica (Linnaeus)
6	Clypeus with two pairs of clypeal setae	D. bicoloricornis Chen
–	Clypeus with three pairs of clypeal setae	D. provostii Fairmaire

To investigate the feeding behavior of the Korean Donaciinae , the classification system proposed by Bieńkowski (2015) was adopted. According to this framework, three distinct feeding patterns were identified. Type I: where the insect inclines its head, turns it to the right or left, and inserts both mandibles into the leaf tissues. Type II: characterized by the insertion of one mandible into the leaf, whereas the other remains on the leaf surface. Type III: the head movement of the insect resembles that of Type II, but both mandibles capture the upper and lower surfaces of the leaf. Based on the observations following this classification, D. lenzi and D. provostii exhibited Type I feeding behavior. Donacia aquatica , D. bicoloricornis , and D. clavareaui displayed Type II feeding behavior, whereas D. flemola and D. koreana sp. nov. exhibited Type III behavior (Fig. 5 ). Notably, although D. koreana sp. nov. engaged in leaf feeding, its primary feeding sites were the flowers of Scirpus wichurae and Eleocharis ussuriensis rather than leaf tissues. Figure 5. Feeding pattern of Korean Donacia . A, B. Type I; C, D. Type II; E, F. Type III. Adult Donaciinae exhibit diverse oviposition behaviors that vary depending on the species and associated host plant ( Bieńkowski 1996 ). In the present study, oviposition types were identified in six species using a combination of laboratory rearing and field observations. Based on these findings, oviposition behaviors can be categorized into three distinct types. Type I: eggs are deposited between overlapping leaves floating on the water surface and subsequently covered with a protective membrane. Type II: eggs are laid inside the stem near the water surface and enclosed by a membrane. Type III: eggs are deposited along the feeding trace on the abaxial side of the host plant and covered with a membrane. Based on these classifications, D. aquatica and D. koreana sp. nov. exhibited Type I oviposition behavior. Donacia bicoloricornis and D. clavareaui exhibited type II oviposition, whereas D. provostii and D. lenzi exhibited Type III oviposition (Fig. 6 ). Figure 6. Oviposition patterns of Korean Donacia . A, B. Pattern I; C, D. Pattern II; E, F. Pattern III. The primary habitats of the Korean Donacia species are aquatic environments with low water flow such as reservoirs, ponds, paddies, rivers, and waterside areas with gentle currents. These habitats are classified as low-, mid-, or high-elevation wetlands based on their altitude. Each species exhibits slight differences in habitat preferences, including environmental conditions, wetland type, and elevation. Donacia lenzi and D. provostii primarily inhabit lowland riverbank wetlands, reservoirs, and slow-flowing streams. D. aquatica and D. bicoloricornis are primarily found in reservoirs and low-elevation wetlands. D. clavareaui occurs in lowland wetlands, D. flemola is found in high-elevation wetlands, and D. koreana sp. nov. primarily inhabits mid-elevation wetlands (Table 2 , Figs 7 , 8 ). Table 2. Habitat of Korean Donacia .

Species	Habitat	Altitude (average)
Donacia aquatica	paddy, pond, reservoir, low-elevation wetland	102–111 m (106 m)
Donacia bicoloricornis	reservoir, pond	3–189 m (45 m)
Donacia clavareaui	low-elevation wetland	12–102 m (57 m)
Donacia flemola	high-elevation wetland	539–932 m (815 m)
Donacia koreana sp. nov.	middle-elevation wetland	539 m
Donacia lenzi	reservoir, low-elevation wetland	1–109 m (40 m)
Donacia provostii	river, reservoir, low-elevation wetland	1–94 m (54 m)

Figure 7. Habitat of genus Donacia . A, B. High-elevation wetland; C, D. Mid-elevation wetland; E, F. Low-elevation wetland. Figure 8. Distribution map of genus Donacia . According to the aquatic plant habitat classification proposed by van der Valk (2012) , aquatic plants are divided into four categories based on their growth forms: terrestrial wetland plants, amphibious plants, floating-leaved aquatic plants, and submerged aquatic plants. The habitats of the Korean Donacia species can be classified as follows: D. lenzi and D. provostii prefer habitats dominated by submerged aquatic plants, with floating leaves ( Nymphaeaceae ). By contrast, D. aquatica , D. bicoloricornis , D. clavareaui , D. flemola and D. koreana sp. nov. prefer habitats with terrestrial wetland plants (Fig. 9 ). Figure 9. Habitat of each species of Korean Donacia (modified after Fossil Insect Research Group for Nojiri-ko Excavation 1985 ). We obtained a 658 - bp fragment sequence of the COI gene from two individuals of D. koreana sp. nov. , and the COI sequences were deposited in GenBank under accession numbers PX 400636 and PX 400637 . Genetic distance analysis based on a 564 bp fragment of the COI gene showed that intraspecific divergence among Donacia species ranged from 0.0 % to 3.9 %, with D. koreana sp. nov. exhibiting no genetic variation (0.0 %). Interspecific genetic distances within the genus Donacia ranged from 9.2 % to 22.9 %, whereas those between D. koreana sp. nov. and D. obscura ranged from 11.2 % to 11.4 % (Fig. 10 ). Figure 10. Maximum-likelihood phylogenetic tree based on COI gene sequences. Bootstrap support values (> 50 %) are indicated above the branches. Plateumaris braccata was used as an outgroup taxon.