Emphytopsis nigromaculata ( Takeuchi, 1952 )

Shinohara, Akihiko, Saito, Takeshi, Ibuki, Shin-Ichi & Hara, Hideho, 2014, Sawflies of the genus Emphytopsis (Hymenoptera, Tenthredinidae) associated with Stewartia (Theaceae) in Japan, Zootaxa 3884 (4), pp. 301-318 : 302-309

Emphytopsis nigromaculata ( Takeuchi, 1952)

( Figs. 1 A–E, 2A–F, 3A–E, 4, 5, 9A–D, I–K, 10)

Taxonus nigromaculatus Takeuchi, 1952: 53 ; Takeuchi, 1955: 124, fig. 848 (paratype from Yanase); Togashi, 1965: 251, pl. 126, fig. 5; Togashi, 1992 (in part): 38; Togashi, 1998: 263; Nakamura, 2003: 260; Nagase, 2004: 1252; Naito et al., 2004: 42; Yoshida, 2006: 71; Nagase, 2007: 291; Togashi, 2008: 496, fig. 2605.

Emphytopsis nigromaculata: Wei et al., 2011: 4 , 14; Wei & Zhou, 2012: 434; Wei & Niu, 2013: 137.

Female. Redescribed in detail by Wei et al. (2011). Serrula of lancet distinctly convex basally, distinctly higher than convex membranous part between serrulae, with distinct denticles ( Figs. 4 , 5 ).

Male (hitherto undescribed) (a specimen from Nakagawa). Length 9 mm. Yellowish white (greenish in life, Fig. 2D–F), with following parts black: Spot including ocelli, apex of mandible, three large spots on mesonotum, FIGURE 2. Emphytopsis nigromaculata (A–F) and E. vernalis , paratypes (G–L), Nakagawa.—A–C, G–I, Females; D–F, J–L, males. All digital images taken by F. Ito just after killing, to retain coloration in life.

one on median lobe and one on each of lateral lobes, mesopostnotum, small spot on each convex part of metascutum anterolateral to each cenchrus, and very narrow stripe along posterior margin of metapostnotum. Inner surface of hind femur apically blackish brown; antennal flagellum and tibiae and tarsi slightly brownish. Wings hyaline, very slightly stained with blackish brown; veins black, with veins C, Sc and R1 and basal parts of anal veins yellowish white; stigma yellowish white, with large blackish brown spot posteroapically.

Structure and punctuation generally similar to female. Anterior margin of clypeus incised to 0.56× clypeal length ( Fig. 3 E); malar space about 0.2× diameter of median ocellus; postocellar area about as long as wide ( Fig. 3 D); head behind eyes in dorsal view much shorter than eye, lateral sides weakly roundly convex, much narrower than across eyes; relative lengths of antennomeres 1–9 about 7: 4: 15: 12: 10: 7: 6: 6: 6 (Fig. 2D, E); hind tarsomere 1 about 0.92× length of tarsomeres 2–5 together. Subgenital plate very broadly rounded with nearly truncate apex. Genitalia as in Fig. 9 A–D, I–K; harpe rather narrow, with inner basal part produced; valviceps in dorsal view ( Fig. 9 A) with outer apical margin rounded, and in lateral view ( Fig. 9 C, D, I–K) with ventral margin not strongly convex and thus anteroventral and posterodorsal margins gently converging towards apex.

Larva (hitherto undescribed). Middle instar ( Fig. 1 C): Head pale brown with round black spot including eye; trunk entirely greenish white; entire insect covered with very thin wax. Last feeding instar ( Fig. 1 A): Similar to middle instar but wax layer slightly thicker. Prepupa ( Fig. 1 B): Similar to last feeding stage but shorter and more vivid in color; wax covering missing and dorsum of trunk inconspicuously darkened.

Variation. Female: The length ranges from 8 to 10.5 mm. The specimens from Nikko are paler than those from other areas, with the black marks on the postocellar area, metapostnotum, and abdominal terga 1 and 2 often reduced or missing. The length/width ratio of the postocellar area ranges from 0.94 to 1.20 (average 1.07) and the ratio of the depth of ventral incision of the clypeus to the entire length of the clypeus ranges from 0.52 to 0.61 (average 0.57). Male: The length ranges from 7 to 9 mm. The color pattern is fairly stable in Tochigi specimens but the specimens from other areas often have more dark marks as follows. The black ocellar spot is often extended onto the anterior part of the postocellar area. The sunken areas of the mesoscutal and metascutal lateral lobes as well as the metapostnotum are often largely or entirely black. The dorsal surface of each abdominal tergum sometimes has paired lateral dark brownish marks. The length/width ratio of the postocellar area ranges from 1 to 1.18 (average 1.08) and the ratio of the depth of ventral incision of the clypeus to the entire length of the clypeus ranges from 0.52 to 0.65 (average 0.6).

Specimens examined. Type material: Holotype: ♀, “ 26. V. 1932, Mt. Sobo, Takeuchi” (OPU). Paratypes: 1♀, “ 3. V. 1951, Yanase, Tosa, Takeuchi” “ Taxonus nigromaculatus Take. , Paratype ” (OPU; in fig. 848, Takeuchi 1955); 1♀, “ 12. VI. 1937, Mt. Kanmuri, Hiroshima, Takeuchi / Coll. T. Nakanisi [underside]” “ Taxonus nigromaculatus Take. , Paratype ” “ Emphytopsis nigromaculatus ( Takeuchi, 1952) , Det. M. Wei, 2010” (OPU). Other material: HONSHU—Tochigi Pref.: 1♂, Nikko-meiho High School, 670 m alt., 3645’03 N 13934 ’42E, Kujira-machi, Nikko-shi, one of 25 larvae coll. 23. VII. 2008, mat. 23–28. VII., em. 2. V. 2009, host: Stewartia pseudocamellia, T. Saito ; 1♀, same data but em. 7. V. 2009; 1♀, same data but em. 11. V. 2009; 1♀, same data but em. 14. V. 2009; 1♀ 5♂, same locality, 11. V. 2009, on Stewartia pseudocamellia, T. Saito ; 2♀ 1♂, same data but 12. V. 2009; 6♀ 7♂, same data but 13. V. 2009; 2♀, same data but 14. V. 2009; 1♀, Bambi Farm, 230 m alt., 3646’58 N 14010 ’29E, Wami, Nakagawa-machi, 9. V. 2012, Malaise trap, S. Ibuki; 1♀, same data but 12. V. 2012; 1♂, same data but 13. V. 2012; 2♀, same data but 16. V. 2012; 1♀, same data but 20. V. 2012; 1♂, same data but 29. IV. 2013; 2♀, same data but 12. V. 2014; 1♂, same data but 14. V. 2014; 1♀, same data but 17. V. 2014; 1♀, same data but 20. V. 2014; 1♀ 1♂, same data but 22. V. 2014; 1♀, same data but 29. V. 2014. Tokyo Met.: 1♀, Yagisawa, Nishitokyo, 30. IV. 2013, T. Keino. Kanagawa Pref.: 1♀ 3♂, Hakone, 2. VI. 1974, A. Shinohara; 1♀, Komagatake, Hakone, 1100–1300 m alt., 5. VI. 2004, H. Nagase; 1♂, Mikunitoge, 1100m alt., 25. V. 2002, H. Nagase; 1♂, Mt. Hirugatake, 1672m alt., 23. V. 1998, M. Kato. Ishikawa Pref.: 1♀, Mt. Dainichi, 16. VI. 1977, I. Togashi; 1♂, Mt. Shiritaka, Tsurugi, 24. VI. 1984, I. Togashi. Shiga Pref.: 2♂, “Mt. Hira, June, 1929, Coll. C. Teranishi”; 1♀, Mt. Hirasan, 3. VI. 1957, O. Sato. Nara Pref.: 1♀, Mt. Odaigahara, 9. VIII. 1957, O. Sato. Tottori Pref.: 1♀, Yokotemichi, 1000 m alt., W. slope of Mt. Daisen, 20–25. V. 2000, A. Shinohara.

Distribution. Japan (Honshu, Shikoku, Kyushu).

Host plant. Theaceae : Stewartia pseudocamellia Maxim. (New record.)

Field observations and rearing records. On July 22, 2008, Saito first found the sawfly larvae on the leaves of Stewartia pseudocamellia in the campus of Nikko-meiho High School in Kujira Town, at an altitude of 670 m, Nikko City, Tochigi Prefecture. On July 23, 25 larvae were collected and reared in a container. Three larvae executed extra molt and became prepupae on July 23, eight larvae did the same on July 24, five larvae on July 25, five larvae on July 26, three larvae on July 27 and one larva on July 28. All the prepupae went into the soil soon after the extra molt. In the soil, the prepupa made an earthen cell and stayed inside. One male adult emerged on May 2, 2009, and one female adult each emerged on May 7 and 14, respectively.

From May 11 to 25, 2009, adults were found gathering on the foliage of the host plant in the same locality. They were active already at 7: 30 in the morning. Saito first found feeding young larvae on May 14 and they were numerous on June 2. On June 12, several larvae were put in a rearing container; one larva became a prepupa and went into the soil on June 27 and one larva each on July 1 and 2 ( Fig. 1 B), respectively. On August 15, Saito examined the earthen cells in the soil in the container. The cells were made of hardened soil and measured about 5 × 10mm.

Saito also observed the occurrence of a large number of larvae at the same site on June 26, 2010.

The egg is laid into the tissue on the underside of a leaf, one egg per leaf. The larva is solitary. The young larva infests surface tissues on the underside of the leaf eventually making a small round hole ( Fig. 1 D), whereas the late instar larva also eats margins of the leaves (as in Fig. 1 I). The prepupa is quite active before entering the soil.

Remarks. This species is very similar to E. flatoserrula and E. shinoharai . The three species are distinguishable mainly by the shape of the lancet of the ovipositor as shown in the key. The male is known only for E. nigromaculata among the three species.

Taxonus nigromaculatus was described from three females, the holotype from Kyushu and one paratype each from Shikoku and Honshu ( Takeuchi, 1952). In Takeuchi’s collection, we found three females, two of which had the paratype labels. The remaining female is labeled “ 26. V. 1932, Mt. Sobo, Takeuchi” and had no type labels but it is doubtless the holotype, because its collection data perfectly agree with those of the holotype mentioned in the original description.

Figures

FIGURE 1. Emphytopsis nigromaculata, Nikko (A – E) and E. vernalis, Kanuma (F – K). — A, Last feeding instar larva, July 2, 2009; B, prepupa, July 2, 2009; C, middle instar larva, June 14, 2009; D, damages of a leaf of Stewartia pseudocamellia by early to middle instar larvae, June 14, 2009; E, adult female, May 17, 2009; F, last feeding instar larva, June 15, 2008; G, prepupa, June 12, 2009; H, prepupa just after extra molt and cast skin, June 17, 2008; I, damages of leaves of S. pseudocamellia by late instar larvae, June 15, 2008; J, two eggs deposited in a young leaf of S. pseudocamellia, May 1, 2012; K, adult female, April 19, 2009. All digital images taken by T. Saito.

FIGURE 3. Heads (A – L) and apical ovipositor sheath (M), E. nigromaculata (A – E), E. flatoserrula (F), E. shinoharai (G) and E. vernalis (H – M). — A – C, Female, holotype; D, E, male, Nakagawa; F – J, M, females, holotypes; K, L, male, Nakagawa, paratype.

FIGURE 4. Emphytopsis nigromaculata, lances and lancets, Mt. Sobo, Kyushu, holotype, (A – D) and Yanase, Shikoku, paratype (E – H). — A, E, Whole lances and lancets; B, F, 1 st to 5 th serrulae; C, 7 th to 11 th serrulae; D, apex of lance and lancet, showing 12 th to terminal serrulae; G, 5 th to 10 th serrulae; H, apex of lance and lancet, showing 13 th to terminal serrulae.

FIGURE 5. Emphytopsis nigromaculata, lancets, Honshu, Nakagawa (A – D) and Nikko (E – G). — A, E, Whole lancets; B, 1 st to 5 th serrulae; C, 6 th to 10 th serrulae; D, apex of lancet, showing 11 th to terminal serrulae; F, 1 st to 3 rd serrulae; G, apical part of lancet, showing 4 th to terminal serrulae.

FIGURE 9. Male genitalia, E. nigromaculata (A – D, I – K) and E. vernalis, paratypes (E – H, L – N). — A, E, Genital capsules, dorsal view; B, F, do., ventral view; C, G, I – N, penis valves, lateral view (left dorsal); D, H, valviceps. A – D, K, Nikko; E – J, L, Nakagawa; M, Kanuma; N, Shin-onsen.