Pamphilius kamikochensis Takeuchi, 1930

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 : 194-195

Pamphilius kamikochensis Takeuchi, 1930

Japanese name: Ko-haraaka-hirata-habachi

( Fig. 2 )

Larva. Middle instar ( Fig. 2D, E ): Head black with antennae creamy white; trunk including all appendages creamy white with most of prothoracic shield and part of cervical sclerite black. Final instar ( Fig. 2F ): Head black with antennae pale green; trunk including all appendages pale green with part of prothoracic shield and cervical sclerite black.

Host plant. Rosaceae : Padus ssiori (F.Schmidt) C.K.Schneid.

Life history. This species has a univoltine life cycle as other Pamphilius species. The adults are on wing in spring (e.g., middle of May to middle of June in Shôbugahama, ca. 1280 m alt., Nikko, in central Honshu, Fig. 2A, B ; see also National Museum of Nature and Science, 2022, for adult collection records). The female lays an egg along the main vein in the basal part of the underside of a leaf ( Fig. 2C, G ). The larval abode is a com- mon simple leaf-roll on the underside of the leaf ( Fig. 2G–H ). The larva is solitary. The egg and larval period apparently takes about a month.

Remarks. Shinohara and Okutani (1983) first recorded Padus ssiori as the host plant of Pamphilius kamikochensis . They noted lOn 5 June 1977, Shinohara encountered an outbreak of this species in Nikko-Yumoto, ca. 1700 m alt., Tochigi Pref., Honshu.z Since 1977, Shinohara has occasionally seen a large number of the adults and larvae on P. ssiori (possibly described as loutbreakz in some cases) in Tochigi Prefecture and Nagano Prefecture, Honshu (for some collection data, see National Museum of Nature and Science, 2022). The larvae and leaf-rolls are described and illustrated here for the first time. The larvae are easily recognized by the host plant, the entirely black head capsule and the entirely pale abdomen.

This is one of the three species of the Pamphiliidae known to be associated with the rosaceous genus Padus ( Shinohara and Wei, 2016) . It is noteworthy that no larvae of this sawfly have been found on another species of Padus , P. grayana (Maxim.) C.K.Schneid. , which sometimes grows near P. ssiori , even under the loutbreakz conditions. Pamphilius kamikochensis seems to be strictly monophagous.

Figures

Fig. 2. Pamphilius kamikochensis: A, Adults on the leaves of Veratrum sp. under the host tree (13 individuals rec- ognizable), 23. V. 2022; B, female, 1. VI. 2022; C, egg (arrowed) on a leaf, 1. VI. 2022; D, E, middle instar larva, 27. VI. 2022; F, mature larva, 10. VII. 2022; G, two leaf-rolls of probably middle instar larvae and remains of egg shell on a leaf, 26. VI. 2022; H, one leaf-roll of probably late instar larva on a leaf, 26. VI. 2022.A–C, G, H, Nikko; D–F, Tsukuba (indoors). Photographed by Shinohara.