Strongylogaster baikalensis Naito, 1990

Macek, Jan, 2010, Taxonomy, distribution and biology of selected European Dinax, Strongylogaster and Taxonus species (Hymenoptera: Symphyta), Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 253-271 : 257-258

Strongylogaster baikalensis Naito, 1990

( Figs. 3 , 11 , 13 , 22 )

Material examined. CZECH REPUBLIC: BOHEMIA centr.: Český kras PLA: Hostim env., Kačák brook (6050), 31.v.2007, 1 spec., MT, J. Macek lgt. BOHEMIA or.: Železné hory PLA: Krkanka NR (6160), 2.vi.2004, 11 spec., 30.vii.2004, 8 spec. ; Údolí Doubravy NR (6159), 25.v.2005, 2 spec., 16.vi.2005, 2 spec., all F.Bárta ( MT). BOHEMIA bor.: Jizerské hory PLA: Ztracený potok brook, Kyselka (5257), 2.vi.–30.vi.2006, 2 spec., P. Vonička lgt. ( YPT) ; České Švýcarsko NP: Dolský mlýn mill (5152), 15.v.2005, 2 spec., 25.v.2005, 1 spec., 16.vi.2005, 2 spec. ; Vlčí potok brook (5052), 2.vi.2008, 1 spec. ; Suchá Bělá brook (5151), 22.v.2005, 1 spec., all M. Trýzna lgt. ( MT) ; Brtnický most bridge (5052), 2.vii.2008, 1 larva on Matteuccia , adult emerged 30.iii.2009, J. Macek lgt. BOHEMIA occ.: Sokolov distr.: Dasnice (5841), 23.v.2006, 1 spec., 13.vi.2006, 1 spec. ; Kaceřov (5840), 21.v.2006, 1 spec., 29.vi.2006, 1 spec. ; Dolní Nivy (5741), 10.vi.2004, 2 spec., Horní Nivy (5741), 10.vi.2006, 3 spec., all J. Macek lgt. ( MT) and det. ( NMPC) .

Adult. Redescription. Body length 6–8.5 mm. Head and thorax black, labrum, clypeus, upper angles of pronotum and tegulae whitish; legs brown; abdomen black, most of terga 2 and 3 and middle of terga 4 and 5 orange yellow, posterior margin of each tergum, laterotergites and marks on sterna white; abdomen of males mostly black with inconspicuous orange-yellow spot medially ( Fig. 3 ). Body longitudinally cylindrical, head coriaceous with smooth, sharply margined frontal field, frontal pit larger than frontal ocellus, coriaceous; postocellar area convex with deep pits flanking posterior ocelli; temples even, clypeus finely emarginate, dull; antennae in females a little shorter than abdomen, in males as long as abdomen, antennomeres slightly shortening towards apex; mesonotum smooth and lustrous, mesoscutellum with sparse punctuation, mesopleuron finely coriaceous, wings slightly nebulous, venation black, yellowish basally; anal cell without crossvein, tarsal claw simple; abdomen finely reticulate; ovipositor sheath slender with pointed dorsoapical projections, cerci as long as ovipositor sheath.

Notes on identification. Strongylogaster baikalensis differs from the similar S. macula by the characteristic colour pattern on the abdomen: the orange-yellow marks are reduced to the middle part of the abdomen and never merged with the white spots on laterotergites, and the abdomen is mostly black in males. Penis valve as in Fig. 13 .

Larva. Description. Ground colour green, dorsal part darker and finely mottled, head orange yellow with brownish vertex; dorsal vessel more or less transparent and flanked by dark longitudinal stripes; abdominal segments with six annulets; annulets 1, 2 and 4 with 3–5 short setae and annulets 2 and 4 with two additional small conical tubercles; subspiracular and surpedal lobe with 4–5 setae and 1–2 small conical tubercles; suranal lobe densely setaceous; prolegs with 6–7 setae on outer side ( Fig. 11 ).

Notes on identification. The larvae differ from those of S. macula by the finely mottled dorsal ground colour and more transparent dorsal vessel. The host plants are also different (see below).

Bionomics. Univoltine. Flight period from mid May to mid June; larval period from May to June. Host plants: Dryopteris filix-mas (Dryopteridaceae) and Matteuccia struthiopteris (Woodsiaceae) (new records).

Distribution. Russia (Baikal region) ( NAITO 1990, 1996); Czech Republic (new record) ( Fig. 22 ).

Comments. Strongylogaster baikalensis belongs to the S. macula group characterised by a peculiar form of the ovipositor sheath and yellow clypeus ( NAITO 1996). It has never been found again since the description. When revising a large series of S. macula from various parts of the Czech Republic, I have recognized that it also includes specimens that agree well with the original description of S. baikalensis ( NAITO 1990) . Both species seem to be widely distributed throughout the Czech Republic; S. macula is associated with Athyrium filix-femina and S. baikalensis with Dryopteris filix-mas and Matteuccia struthiopteris .

Figures

Figs. 2–7. Strongylogaster Dahlbom, 1835, adults: 2 – S. macula (Klug, 1817); 3 – S. baikalensis Naito, 1990; 4 – S. mixta (Klug, 1817); 5 – S. filicis (Klug, 1817); 6 – S. multifasciata (Geoffroy, 1785); 7 – S. xanthocera (Stephens, 1835). Scale: 10 mm.

Figs. 8–12. Strongylogaster Dahlbom, 1835, larvae: 8 – S. xanthocera (Stephens, 1835): a – immature instar (dorsal view); b – last instar (lateral view); c – last instar (laterodorsal view). 9 – S. multifasciata (Geoffroy, 1785): a – last instar (laterodorsal view); b – last instar (dorsal view). 10 – S. macula (Klug, 1817): last instar (laterodorsal view). 11 – S. baikalensis Naito, 1990: last instar (laterodorsal view). 12 – S. mixta (Klug, 1817): a – immature instar (laterodorsal view); b – last instar (lateral view); c – last instar (lateral view). Scale for last instar larva: 10 mm.

Figs. 13–14. Strongylogaster Dahlbom, 1835, penis valve, lateral view: 13 – S. baikalensis Naito, 1990; 14 – S. macula (Klug, 1817). Scale: 0.5 mm.

Fig. 22. Known localities of Strongylogaster baikalensis Naito, 1990 in the Czech Republic.