Nipponorhynchus bimaculatus Naito, 1973

Smith, David R. & Naito, Tikahiko, 2015, Studies on Adelestini (Hymenoptera, Tenthredinidae), particularly the long-tongued Nipponorhynchus Takeuchi of Japan, Journal of Hymenoptera Research 45, pp. 1-14 : 2

Nipponorhynchus bimaculatus Naito

Figs 2 , 6 , 10 , 14 , 19 , 23 , 24 , 27-29

Nipponorhynchus bimaculatus Naito, 1973: 95, fig. 1.

Description.

Female: Length, 5.0 mm. Antenna and head black; anterior half of clypeus dark brown, labrum and upper surface of maxillolabial complex whitish; palpi and undersurface of maxillolabial complex dark brown. Thorax black with tegula and posterior corners of pronotum whitish. Legs black with apices of coxae, trochanters, apical quarter of femora, tibiae except apical quarter with black stripe on inner surface and basitarsomeres whitish. Abdomen black (terga 2 and 3 often with yellow mark in male); center of apical tergum and cercus whitish. Wings hyaline; veins and stigma black. Head very shiny, almost impunctate; inner orbits, gena and clypeus with fine irregular punctures. Thorax and abdomen very shiny, sometimes terga 3-9 finely reticulate; posterior margin of mesoscutellum with several large punctures.

Antenna length 1.7 × head width, with scape and pedicel each longer than broad; 3rd antennomere length 1.3 × 4th, 4th to 9th antennomeres gradually decreasing in length. Clypeus slightly broadly, circularly emarginated, about 3 × broader than long. Malar space about equal to diameter of median ocellus. Lower interocular distance 1.3 × eye height; eyes only slightly converging below. Maxillolabial complex about 1.0-1.1 × head width and about 2.2 × eye height; maxillary palpus about 0.6 × length of proboscis, longer than distance between maxillary palpus and labial palpus. Distances between eye and lateral ocellus, between lateral ocelli, and between lateral ocellus and hind margin of head as 1.0:0.8:0.5. Interocellar furrow represented by small pit. Postocellar furrow defined. Postocellar area 1.5 × broader than long. Posttergite distinct, length:width as1:4, triangular behind. Tarsal claws simple. Hind basitarsomere subequal to length of following 3 tarsomeres combined. Sheath in lateral view straight above, rounded at apex and below; from above, equally wide throughout. Lancet in Fig. 19 ; 10 or more annular spines in two or three rows.

Male: Described by Naito (1973). Gentialia (Figs 23 , 24 ), penis valve with valviceps almost round and apex somewhat flattened, dorsal spine slender.

Specimens examined.

JAPAN: Honshu, Bicchuzawa, Bato, Tochigi Pref. 15.IV.2004, K. Katayama (1♀); same locality, 23.IV.2005, T. Naito (2♂); same locality, 24-30.IV.2005, S. Ibuki (4♀), same locality, 23, 29.IV.2005, A. Shinohara (2♀); same locality, 16-17.IV.2012, S. Ibuki (3♀); same locality, 29.III.2012, S. Ibuki (emerged from Chrysosplenium macrostemon Maxim var. shiobarense (Franch. Hara))(2♀); Akazai-keikoku, Hyogo Pref. 20.V.1999, T. Okushima (1♀); Onzui-keikoku, Hyogo Pref., 21.IV.2008, T. Naito (1♀); Mt. Ooginosen, Hyogo Pref., 22.V.2006, T. Naito (1♀, 1 ♂); same locality, 7.V.2012, T. Naito; Mt. Hachibuseyama, Hyogo Pref., 5.V.2013, T. Naito (1♀); Honshu, Oodaigahara, Nara Pref., 7.VI.1976, T. Naito (1 ♂ paratype); Honshu, Bicchuzawa, Bato, Tochigi Pref., 23.IV.2005, T. Naito (2 ♀, 1 ♂); Hyogo Pref., Onzui-keikoka, 700 m, 21.IV.2008, T. Naito (1 ♀).

Distribution.

Japan (Honshu).

Host and biological notes.

TN observed adult habits on the host plant in April 2005 at Bicchuuzawa, Tochigi Pref., Japan. Later, Saito and Ibuki (2010) succeeded in rearing this sawfly. Adults appear in early spring and fly on the flowers of the host plant, Chrysosplenium macrostemon Maxim var. shiobarense (Franch. Hara) ( Saxifragaceae ). They insert the long proboscis into the flower and absorb the nectar (Fig. 27 ). Females cut the seed capsule of the host plant with the sawlike ovipositor and lay their eggs into the capsule (Fig. 28 ). Larvae mainly eat young seeds and bracts (Fig. 29 ). Mature larvae fall to the ground, enter it, and make a fragile cocoon of soil particles held together by saliva (similar to N. mirabilis , Fig. 31 ). They overwinter in the prepupal stage.

The life cycle of N. mirabilis is quite similar to N. bimaculatus , and the host plant is the same for both species. The two species coexist in Honshu, Japan, where N. mirabilis appears somewhat earlier than N. bimaculatus . The body of the larva is light brown in both species, but the head is light brown in N. bimaculatus (Fig. 29 ), whereas it is black in N. mirabilis (Fig. 30 ) ( Saito and Ibuki 2010).

Figures

Figures 1 - 4. Head, front view. 1 Nipponorhynchus mirabilis 2 N. bimaculatus 3 N. brevis 4 Adelesta nova.

Figures 5 - 8. Head, lateral view. 5 Nipponorhynchus mirabilis 6 N. bimaculatus 7 N. brevis 8 Adelesta nova.

Figures 9 - 16. 9 - 12 Head, dorsal view. 13 - 16 Apex of mesonotum showing posttergite 9, 13 Nipponorhynchus mirabilis 10, 14 N. bimaculatus 11, 15 N. brevis 12, 16 Adelesta nova.

Figures 17 - 20. 17 Nipponorhynchus brevis, lateral view 18 - 20 Female lancets 18 N. mirabilis 19 N. bimaculatus 20 N. brevis.

Figures 21 - 26. Male genitalia. 21, 23, 25 Genital capsule, ventral view 22, 24, 26 Penis valve, lateral view 21, 22 N. mirabilis 23, 24 N. bimaculatus 25, 26 N. brevis.

Figures 27 - 31. Nipponorhynchus spp. and the host plant, Chrysosplenium macrostemon var. shiobarense. 27 N. bimaculatus, adult drinking honey of the host plant 28 N. bimaculatus adult female ovipositing into a seed capsule of the host plant. 29 N. bimaculatus larva eating young seeds of host plant 30 N. mirabilis, larva eating young seeds of host plant 31 N. mirabilis pupa in cocoon in soil.