Dasineura heterosmilacicola Kato & Kawakita, 2025, sp. nov.
Creators: name: Kato, Makoto
name: Kawakita, Atsushi
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Cecidomyiidae
Dasineura
Dasineura heterosmilacicola

description: Dasineura heterosmilacicola sp. nov.
Figs 3, 4, 5, 6, 7
Material examined.
Holotype: Japan • 1 ♂, NSMT -I-Dip 36246, microscopic slide; Mt Kubura, Yonaguni Island, Yonaguni-chô, Yaeyama-gun, Okinawa Prefecture; 24.4572°N, 122.9586°E; altitude 90 m; 5-III-2019 (as larva in male flower of Heterosmilax japonica), emerged on 30-III-2019; M. Kato leg.
Paratypes: Japan • 2 ♂ 3 ♀, NSMT -I-Dip 36241 –36245, freeze-dried specimens; NSMT -I-Dip 36247, microscopic slide; same data as holotype, emerged on 30–31-III-2019 M. Kato leg. • 2 ♂ 3 ♀, NSMT -I-Dip 36248 –36250, freeze-dried specimens & NSMT -I-Dip 36251 –36252, microscopic slides; Funaura, Iriomote Island, Taketomi-chô, Yaeyama-gun, Okinawa Prefecture; 16-IV-2023 (as larva in male flowers), emerged on 5–8-V-2023; M. Kato leg. • 1 ♂ 2 ♀, NSMT -I-Dip 36253 –36255, freeze-dried specimens); Funaura, Iriomote Island, Taketomi-chô, Yaeyama-gun, Okinawa Prefecture; 5-VI-2018 (as larva in male flowers), emerged on 19–20-VI-2018; M. Kato leg.
Other material.
Japan • 1 ♂ 3 ♀; same data as holotype, emerged on 30–31-III-2019 • 1 ♂ 3 ♀; Funaura, Iriomote Island, Taketomi-chô, Yaeyama-gun, Okinawa Prefecture; 5-VI-2018 (as larva on male flower), emerged on 19–22-VI-2018 • 1 ♂ 3 ♀; Funaura, Iriomote Island, Taketomi-chô, Yaeyama-gun, Okinawa Prefecture; 16-IV-2023 (as larva on male flower), emerged on 8-V-2023 • 1 ♂ 4 ♀; Higashinakama, Amami-Ôshima Island, Kagoshima Prefecture; 13-VI-2018 (as larva on male flower), emerged on 1-VII-2018; all these non-types M. Kato leg.
Diagnosis.
A small species (wing length 1.2–1.5 mm); antenna with 12–13 flagellomeres in males, 11–12 in females. Eyes holoptic, with a distinct constriction at the middle. Tarsal claws bifid, each strongly curved downward beyond mid length. Male gonostylus basal 1 / 3 swollen, apically forming a dark brown sclerotized claw. Female abdomen with segments 7–8 protrusive; extended ovipositor 9–10 × as long as 7 th tergite; eighth tergite divided into two separate, narrow longitudinal sclerites, with a pair of anterior granular sensillae. Larva feeds on internal tissue of fallen male flower of Heterosmilax japonica (Smilacaceae).
Description.
Adult male (Figs 3, 4):
Head (Fig. 3 E, H, M): eyes holoptic, with a distinct constriction at the middle, along the frontal margin around antennae sockets. Eye facets circular; eye bridge 5–6 facets long. Antenna (Fig. 3 C): scape and pedicel white and rounded; pedicel 2 / 3 as long as the scape (Fig. 3 H); flagellomeres 12–13, brownish, with short, naked neck; neck length about 1 / 4 as long as node; circumfila composed of a continuous sub-basal band joined with a partial subapical band; 13–15 long subapical and 12–14 short sub-basal setae with enlarged alveoli (Fig. 3 G, J – L). Palpus 4 - segmented; segments 2–3 of similar length, 1.7 times as long as the 1 st and 0.66 times as long as the 4 th (Fig. 3 I, M); each segment with several strong setae and covered by brownish scales (Fig. 3 H).
Thorax: wing (Fig. 3 B) length 1.3–1.4 mm; R 1 joining C before mid-length of wing; R 5 curving anteriorly and joining C before wing apex. M 3 + 4 connected with Cu, forming a fork. Wing membrane with dense, dark microtrichia. Halter brownish. Scutum, scutellum, mediotergite, propleuron, anepisternum, katepisternum, and katatergite brown; other parts whitish (Fig. 3 D). Anepisternum with 5–6 setae on dorsal third; anepimeron with 7–8 setae; remaining pleura bare.
Legs slender and brown, but inner sides paler. Tarsal claws bifid on all legs; each claw strongly curved downward beyond mid-length; empodia as long as tarsal claws (Fig. 3 F).
Abdomen: tergites 1–6 rectangular, each with a single row of setae along posterior margin and lateral setae, elsewhere mostly covered with brownish scales; 7 th tergite unsclerotized, with a pair of medial setae (Figs 3 D, 4 A); 8 th tergite unsclerotized. Sternites 1–7 rectangular, divided transversely, sclerotized as two pigmented transversal bands, each bearing a row of setae; 8 th sternite smaller than others, emarginate posteromedially (Fig. 4 A, B), setulose.
Terminalia (Fig. 4 C – G): gonocoxite stout cylindrical, setulose, with setae on apical half and densely setose inward. Gonostylus tapering distally, weakly arched inward, sparsely setulose, apically forming dark-brown sclerotized claw. Mediobasal lobe subdivided, sheathing aedeagus, slightly shorter than aedeagus, densely covered with setulae directed backward. Hypoproct shorter than cerci, with narrow lobes, U-shaped incision about 1 / 3 length of hypoproct, uniformly covered with microtrichia and with one apical seta on each lobe (Fig. 4 G). Cerci ovate, deeply separated, setose distally. Aedeagus with subtriangular apex.
Adult female (Figs 5, 6)
Head: similar to male except the antenna. Antenna (Fig. 5 C); scape and pedicel pale and rounded, pedicel 2 / 3 as long as scape (Fig. 5 D, G); 11–12 flagellomeres (Fig. 4 C), brownish without neck; circumfila composed of a continuous sub-basal band and a partial subapical band joined by two connectives: dorsally with 6–7 basal setae with large alveoli; ventrally with 6–7 long subapical and 6–7 short sub-basal setae with enlarged alveoli (Fig. 5 I, J).
Thorax: wing (Fig. 5 E) length 1.2–1.5 mm. Wing venation similar to male. Notum pale brown with a pair of dark longitudinal stripes covered by long setae and brownish scales (Fig. 5 C). Legs similar to male (Fig. 5 K).
Abdomen: tergites 1–6 rectangular, 5 th – 6 th each narrower than the previous one; all with single row of posterior setae, elsewhere mostly covered with scales (Fig. 5 B, D); 7 th tergite narrow, with many setae on posterior margin, covering only the anterior half of 7 th segment; posterior half naked without scale; 8 th tergite divided into two separate, narrow longitudinal sclerites; sclerites slightly divergent anteriorly and subparallel posteriorly, with a pair of anterior granular sensillae (Fig. 5 B). Sternites 1–7 rectangular, divided transversely, sclerotized as two pigmented transversal bands, each bearing a row of setae (Fig. 6 C). Long tubular ovipositor, usually housed in segments 6–8, but protruding and extended at oviposition (Fig. 6 F, G); extended ovipositor (from base of 8 th segment to cercus apex) 9–10 × as long as 7 th tergite. Cerci as long as 7 th tergite, fused medially into a single terminal lamella, evenly microtrichose; hypoproct narrow, microtrichose, with a pair of distal setae (Fig. 6 E).
Larva. full-grown larva (Figs 2 H, 7): yellowish white, cylindrical, slightly flattened dorso-ventrally, pointed anteriorly, blunt posteriorly (Fig. 2 H). Head capsule hemispherical, cephalic apodemes about as long as head capsule, antennae about twice as long as wide (Fig. 7 A, B). Sternal spatula anteriorly bidentate with V-shaped emargination, slightly extended laterally just posterior to teeth; length / width ratio is 3–4 (Fig. 7 C, D). Thoracic and abdominal segments dorsally with three inner and two outer lateral papillae on each side; each papilla with seta, except the central inner papilla (Fig. 7 A, E). Terminal segment dorsally with eight terminal papillae, each with seta (Fig. 7 E).
Etymology.
The name heterosmilacicola denotes living on Heterosmilax.
Japanese name.
Karasukibasankirai-hana-tamabae.
Host plant.
Male flower of Heterosmilax japonica (Smilacaceae).
Biological notes.
An adult female visits a male flower of the host plant species and lays an egg in the perianth tube. The larva grows by feeding on the pollen and the floral tissue of the fallen male flower. This species is the obligate pollinator of the host plant, breeding in fallen male flowers.
Distribution.
Japan: Ryukyu Archipelago.
Remarks.
So far, 10 Dasineura species are known from Japan (host plant: Pinaceae 3 spp., Fabaceae 3 spp., Symplocaceae, 1 sp., Rubiaceae 1 sp., Asteraceae 1 sp., Adoxaceae 1 sp.: Yukawa 1971; Elsayed et al. 2017). No species has been collected from monocots, and there are no described species closely related to this one. The species resembles D. wisteriae, which induces gall formation on flower buds of Wisteria (Fabaceae) (Nakawatase and Yukawa 1984), but there are fewer flagellomeres than in the latter (male: 12–13 vs 14–15), and the life cycle is multivoltine (the latter univoltine). This species most closely resembles D. camassiae, whose larva grows in the flower bud galls of two monocot species of Camassia (Asparagaceae, Agavoideae), but is discriminated from the latter by the number of flagellomeres (male: 12–13 in this species, 13–15 in the latter; female: 11–12 in this species, 13–14 in the latter), the morphology of the male terminalia (cerci deeply incised in this species, but shallowly incised in the latter), the morphology of the female 7 th tergite (subparallel in the former, but distinctly constricted at the middle in the latter), and the larval morphology (tergite dorsally in each side, with five papillae in the former and four in the latter; length / width ratio of sternal spatula is 3–4 in this species and 7–8 in the latter).
description: Published as part of Kato, Makoto & Kawakita, Atsushi, 2025, Novel brood-site pollination mutualism between sympetalous Heterosmilax (Smilacaceae, Liliales) and a cecidomyiid gall midge (Cecidomyiidae, Diptera) breeding in fallen male flowers, pp. 397-416 in ZooKeys 1234 on pages 397-416, DOI: 10.3897/zookeys.1234.146453