Caliroa vaccini Okutani, 1965

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 : 201-204

Caliroa vaccini Okutani, 1965

Japanese name: Natsuhaze-namekuji-habachi

( Fig. 6 )

Caliroa vaccini Okutani, 1965: 30 ; Hara, 2019: 65; Hara and Ibuki, 2020: 316 .

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

Additional description. The legs of the overwintering generation ( Fig. 6A–C ) are darker than those of the non-overwintering generation ( Fig. 6D ; see also Hara and Ibuki, 2020) and are as follows: black; fore and middle legs brown on narrow apices of femora, yellow on tibiae and tarsus except for their apices slightly brownish; hind tibia yellow except apical 1/3–1/2 dark brown; hind tarsus dark brown, often basally brown yellow narrowly.

In specimens from Nakagawa, clypeus with depth of ventral emargination 0.14–0.29× median height of clypeus, and mesoscutellar appendage often widely covered with setae pos- terolaterally.

Larva. First instar ( Fig. 6F ): head black; trunk pale green. Semifinal (final feeding instar) ( Fig. 6G, H ): head black; trunk pale yellowish white, with thorax mostly yellow; slime transparent. Final instar: almost entirely yellow.

Material examined. Honshu: Tochigi Pref.: 4 $, Nakagawa, Wami, 36°47′N 140°10′E, coll. larvae on Vaccinium oldhamii , 5. X. 2020, mat. 6. X., em. 17, 24. IV. 2021, S. Ibuki ( Fig. 6A–C, E, G, H ); 19 $2 Ə, same data but coll. larvae 2. VI. 2021, mat. 3. VI., em. 17. VI. 2021; 20 Ə, progeny of 1 $ em. 17. VI. 2021, eggs laid 18. VI., larvae hatch. 25. VI., mat. 5–7. VII., em. 16–18. VII. 2021 ( Fig. 6E, F ); 42 $12 Ə, same locality and collector but coll. eggs 18. VI. 2021, larvae hatch. 22. VI., mat. 3. VII., em. 14–15, 17. VII, 2021; 5 $2 Ə, same data but coll. larvae 11. VII. 2021, mat. 13, 16. VII., em. 23, 28. VII. 2021; 3 $, same data but, 36°47′N 140°11′E, coll. larvae 8. VII. 2021, mat. 11–12. VII., em. 21, 25. VII. 2021. For more material, see Hara and Ibuki (2020).

Host plant. Ericaceae : Vaccinium oldhamii Miq. ( Okutani, 1965, see also Hara and Ibuki, 2020).

Host range test. Caliroa vaccini is very similar to C. annulipes (Klug, 1816) from the Russian Far East to Europe and Canada and C. ouensis Hara, 2020 from northern Honshu. The morphological differences of these three species are slight as detailed under the remarks below. Caliroa annulipes is known to be polyphagous ( Schönrogge, 1991). Caliroa ouensis is a rare species and its host plant is unknown. Caliroa vaccini does not appear to be polyphagous, because Ibuki has not found the larva on any plants other than Vaccinium oldhamii in Nakagawa, where he has been enthusiastically investigating sawfly larvae for over 10 years.

To confirm the host range of C. vaccini , we conducted the following experiment: a total of 45 eggs of C. vaccini laid in one leaf of Vaccinium oldhamii collected at Nakagawa on 18 June 2021 were used. In the rearing room in Nakagawa, they hatched on 23 June, were reared on V. oldhamii until 30 June, and then sent alive to Bibai. On 2 July in the rearing room in Bibai, 36 semifinal feeding instar larvae, 4–5 mm long, were selected for the test. Each larva was placed in a transparent polyethylene container with one test plant. The test plants were six species, Vaccinium oldhamii (host), Quercus crispula Blume var. crispula , Tilia japonica (Miq.) Simonk. , Populus tremula L. var. davidiana (Dode) C.K.Schneid. , Betula ermanii Cham. and Rosa × centifolia L. Those plants except for the host plant were selected from the host plant genera or species of C. annulipes studied by Schönrogge (1991). Six larvae were tested for one plant species, and for each of the larvae, the approximate feeding area and the presence or absence of the exuvia were daily recorded until the larva reached maturity (= the final molt) or died.

The results of the experiment are as in Table 1. Larval feeding was observed in all the six plant species. However, some larvae did not feed on four plant species, Quercus crispula , Tilia japonica , Betula ermanii and Rosa × centifolia . In the five plant species other than the host, the feeding areas were very small even if the larva ate the leaves and finally all the larvae died before maturity. These results indicate that C. vaccini is not polyphagous.

Life history. Larvae were found from early June to early October in the field. In the rearing room in Nakagawa, a female laid 20 or more eggs in one leaf, the egg period was seven days, the larval period 10–12 days and the cocoon period (non-overwintering individual) about 11 days. The mature larvae entered the soil and made cocoons. This sawfly is multivoltine. Eggs are laid within the leaf near main or lateral veins ( Fig. 6E ). Larvae are gregarious but they are not in contact with each other ( Fig. 6F, H ). They feed on the under surfaces of leaves ( Fig. 6E–H ). Larvae have an extra molt before maturity. They overwinter in the cocoon.

Remarks. Hara and Ibuki (2020) distinguished C. vaccini from C. annulipes and C. ouensis mainly by the hind leg predominantly pale, the clypeus with the ventral edge shallowly emargin- ated and the middle serrulae of a lancet shallower than and more widely separated from each other than those of the latter two species. The additional specimens from Nakagawa show that the overwintering generation has the widely black hind leg ( Fig. 6C ), which is different from the widely pale hind leg of the non-overwintering generation ( Fig. 6D ) and is very similar to those of C. annulipes (see images in Taeger et al., 2018) and C. ouensis (see fig. 2D in Hara and Ibuki, 2020). The ventral edge of the clypeus is sometimes rather deeply concave in C. vaccini ; the ratio of the depth of the emargination to the medial height of the clypeus partly overlaps between C. vaccini (0.1–0.3) and the latter two species (0.3–0.5). Some specimens of the overwintering generation of C. vaccini may be indis- tinguishable from the latter two species in color and external form. However, those will be separated from C. annulipes and C. ouensis by the middle serrulae of the lancet more widely separated from each other than those of the latter two (compare fig. 8D with fig. 8F, H, I in Hara and Ibuki, 2020) and the harpe of the male genitalia with the lateral margin almost straight or slightly concave (compare fig. 11J in Hara and Ibuki, 2020 with fig. 11M in Hara and Ibuki, 2020 and fig. 5D in Hara, 2011).

Figures

Fig. 6. Caliroa vaccini: A–C, Female, overwintering generation, head in anterior view, whole body in dorsal and ventral views; D, female, non-overwintering generation, ventral view; E, female and her eggs (in leaf tissues, some arrowed), 18. VI. 2021; F, first instar larvae and egg marks (arrowed), 22. VI. 2021; G, H, final feeding instar larvae and leaves eaten by larvae, 5–6. X. 2020; I, leaves eaten by larvae, 2. VI. 2021. A–D, Photo- graphed by Hara; E–I, photographed by Ibuki.