Siobla japonica Shinohara, Wei and Niu, 2013

Fu, Yuanzun, Yuan, Yuan, Shen, Qian, Xu, Hao, Ye, Zheng, Guo, Li, Wu, Xiaoliang & Zhao, Yunhe, 2021, Taxonomic Notes and New Distribution and Host Plant Records for Sawflies and Woodwasps (Hymenoptera, Symphyta) of Japan VI, Bulletin of the National Museum of Nature and Science. Series A, Zoology 47 (4), pp. 163-188 : 184

Siobla japonica Shinohara, Wei and Niu, 2013

Japanese name: Nihon-koshiaka-habachi

( Fig. 9H–I )

Material examined. HONSHU: Tochigi Pref.: 1˂, Nakagawa, Wami, 33°45′N 140°09′E, coll. larva, on Impatiens textorii or Circaea mollis , 5. VI. 2019, mat. 8. VI., em. 8. IV. 2020, S. Ibuki; 1ˁ, Nakagawa, Wami, 33°45′N 140°09′E, coll. larva, on Impatiens textorii or Circaea mollis , 5. VI. 2019, mat. 9. VI. ( Fig. 9I ), em. 11. IV. 2020, S. Ibuki.

Larva. Late instar ( Fig. 9H ): head purplish black; trunk and legs creamy white, dorsal region dark gray, sparsely covered with irregular black spots, each segment with paired yellowish dorsolateral thorns, and black line along ventral margin of pleural region. Mature larva ( Fig. 9I ): blackish, shiny; thoracic legs creamy white.

Host plants. Balsaminaceae : Impatiens textorii Miq. (new record). Onagraceae : Circaea mollis Siebold et Zucc. (new record).

Life history. This is a univoltine species. The larva is a solitary external feeder and, when matured, it has an extra molt before entering the soil.

Remarks. This species is fairly common in central Honshu ( Shinohara et al., 2013), but its immature stages and host plants were totally unknown. Like the preceding species, S. ferox , S. japonica seems to be a polyphagous species with long larval feeding period. The larva of this species may be distinguished from that of S. ferox by the dark color pattern of the head and dorsal region of the trunk in the feeding stages (compare A–C, E–F with H in Fig. 9 ) and the creamy white thoracic legs of the mature larva (compare D, G with I in Fig. 9 ).

Figures

Fig. 9. A–G, Siobla ferox: A, probably middle instar larva on Glechoma hederacea subsp. grandis, 27. VI. 2016; B, same larva, probably late instar, 12. VII. 2016; C, same larva, 16. VII. 2016; D, same larva, matured, 9. VIII. 2016; E. probably middle instar larva on Actinidia polygama, 14. VI. 2016; F. probably middle instar lar- vae on A. polygama, 19. VI. 2016; G. same larva, 15. VII. 2016. H–I, Siobla japonica: H, last instar larva, 5. VI. 2019; I, mature larva and cast skin above, 9. VI. 2019; J–M, Taxonus shinoharai: J, middle and late instar larvae on Agrimonia pilosa var. japonica, 29. IX. 2019; K, late instar, 29. IX. 2019; L, same larva, matured, 30. IX. 2019; M, male adult, just emerged, 26. X. 2019. All photographed by Ibuki.