Euura damnacanti ( Takeuchi, 1922 )

Ryoo, Seung-Woo, Min, Jin-Young, Son, Seok-Yoon, Choi, Baek-Yong, Choi, Juho & Min, Kyoung-Bok, 2022, Taxonomic Notes and New Distribution and Host Plant Records for Sawflies and Woodwasps (Hymenoptera, Symphyta) of Japan VII, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (4), pp. 193-213 : 204-207

Euura damnacanti ( Takeuchi, 1922)

Japanese name: Aridôshi-habachi

( Figs. 7 , 8 )

Pteronidea damnacanti Takeuchi, 1922: 77 , 80.

Euura damnacanti : Shinohara and Hara, 2015: 173; Shinohara and Hara, 2020: 186.

For more synonymy, see Shinohara and Hara (2020).

Additional description. The females ( Fig. 7A–C ) reared from larvae on Berberis thunbergii slightly differ from the type series described by Shinohara and Hara (2020) as follows: mesoscu- tum entirely black; mesepisternum black entirely or with brown spot posterocentrally; postspiracu- lar sclerite dark yellow, anteriorly black; wing with veins and stigma mostly dark brown; paraantennal field glabrous on medial half; katepim- eron entirely glabrous; fore wing with cell Sc 0.5× as wide as vein C at level of base of vein Rs+M.

Male (previously undescribed). The differences except for usual sexual differences are as follows.

Length 5.5–6.0 mm. Thorax black except pos- terodorsal part of pronotum and tegula yellow ( Fig. 7D–F ). Abdomen ventrally brown yellow to brown. Postocellar area with anterior groove dull or indistinct. Frontal area with anterior ridge medially furrowed or not furrowed. Frontal pit long oval or longitudinal groove. Tergum 8 with procidentia barely developed and posterior edge hardly protruding posteriorly ( Fig. 7K ); tergal hollow slightly indicated. Subgenital plate 0.5– 0.6× as long as hind tibia; apical edge rounded in dorsal or ventral view ( Fig. 7K ). Male genitalia Fig. 8E–G ; parapenis long, with medial edge convex at middle in ventral view; harpe longer than wide, with lateral margin gently rounded, medial margin straight and apex narrowly rounded.

Larva. First to semifinal instars ( Fig. 8H, I (left)): head and thoracic legs mostly black; trunk pale green. Final instar ( Fig. 8I, J ): head brown yellow; trunk pale green; thoracic legs pale yellow, basally partly black.

Material examined. Honshu: Tochigi Pref.: 2 $, Sakura, coll. larvae on Berberis thunbergii , 28. IV. 2019, mat. 11. V., em. 28. III., 2. IV. 2020, S. Ibuki ( Fig. 8A–C ); 2 $4 Ə, Nakagawa, Bato, 36°47′N 140°10′E, coll. larvae on Berberis thunbergii , 17. IV. 2021, mat. 28, 30. IV., 1. V., em. 20, 21, 24, 25. III. 2022, S. Ibuki ( Figs. 7A–K , 8D–H, J ). For more material, see Shinohara and Hara (2020).

Host plants. Rubiaceae : Damnacanthus indicus C.F.Gaertn. var. indicus ( Takeuchi, 1922) . Berberidaceae : Berberis thunbergii DC. (new record).

Additional notes on life history. Three or four eggs were found on the surface of the underside of a leaf, and they were lined up neatly in a trans- verse row ( Fig. 8H ). Several young larvae were found on one leaf, but they were separated from each other ( Fig. 8H ). The larvae were collected in middle and late April in Nakagawa , Tochigi Prefecture. In the rearing room, larvae matured from late April to middle May. The extra molt was not observed before maturity. The mature larvae entered in the soil and became adults in the following spring. This sawfly is univoltine .

Remarks. This sawfly is peculiar and easily identifiable by the medially widely glabrous and laterally ridged paraantennal field, the strongly swollen supraclypeal area, the distinctly furrowed genal orbit, the symmetric mandibles each with one small notch at the middle of the inner edge and the anterior and posterior apical ridges both low ( Fig. 7G–J ), the short ovipositor sheath ( Fig. 7C ) and ovipositor, the tangium of the lancet with sensilla (=pores) ( Fig. 8C ) and the barely developed procidentia of the male abdomen ( Fig. 7K ). The adult specimens reared from B. thunbergii are quite similar to the type specimens reared from D. indicus . These two plants are very distantly related and it is strange that the larvae of this lpolyphagousz sawfly have never been found on other plants in Nakagawa, where Ibuki has been investigating sawfly larvae. It may be necessary to confirm whether D. indicus is a real host plant.

Shinohara and Hara (2020) wrote ltangium without sensillaz for this species, based on the lectotype and the paratype, but the sensilla are distinct in the newly obtained female specimens ( Fig. 8C ). Probably because the lancets of the type specimens were not in good condition (fig. 2N, P in Shinohara and Hara, 2020), they failed to find the sensilla. The tangium has no sensilla in Euura Newman, 1837 , but has sensilla in Pristiphora Latreille, 1810 and some species of Fagineura Vikberg and Zinovjev, 2000 (see Prous et al., 2014, 2017, 2019 and Hara and Ibuki, 2022). Therefore, this species may better be placed in Pristiphora or Fagineura than in Euura . A genetic study may be needed to test this hypothe- sis.

Figures

Fig. 7. Euura damnacanti: A–C, Female, head in anterior view, whole body in dorsal and ventral views; D–F, male, head in anterior view, whole body in dorsal and ventral views; G, H, mandibles, anterior and posterior views; I, J, right and left mandibles in outer view; K, apex of male abdomen in dorsal view. Photographed by Hara.

Fig. 8. Euura damnacanti: A, Lance; B, lancet; C, tangium of lancet; D, basal half of lamnium of lancet; E, F, male genitalia in dorsal and ventral views (penis valve removed in F); G, penis valve; H, first instar larvae and egg shells, 17. IV. 2021; I, final and semifinal instar larvae, Nakagawa, 7. V. 2015; J, mature larva, 30. IV. 2021.A–G, Photographed by Hara; H–J, photographed by Ibuki.