Dinax ermak ( Zhelochovtsev, 1968 )

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 : 254-256

Dinax ermak ( Zhelochovtsev, 1968)

( Figs. 1 , 21 )

Material examined. CZECH REPUBLIC: BOHEMIA mer.: Třeboňsko PLA: Třeboň env., Stříbřecký most bridge (6955), 9.vi.2006, 18 larvae on Spiraea salicifolia , 3 adults emerged, J. Macek lgt .; Borkovice (6753), 31.v.2008, 6 larvae on Spiraea salicifolia , 2 adults emerged, J. Macek lgt., all J. Macek det. ( NMPC) .

Adult. Diagnosis. Black, pronotum, tegulae and hind margins of abdominal terga and sterna with narrow whitish strips; tibiae and tarsi whitish ( Fig. 1 ).

Body length 7–7.5 mm. Head in dorsal view rectangular, lustrous, with temples slightly receding posteriorly; clypeus deeply incised with sharp lateral projections, surface with flat and irregular wrinkles; malar space longer than diameter of front ocellus and almost twice as long as pedicel; occipital carina incomplete, obliterated on vertex, postocellar area longer than wide ( POL: OOCL = 1: 1.5) with distinct divergent postocellar furrows, mandibles asymmetric, left one with two and right one with three teeth; antennae a little longer than abscissa of costa from wing base to pterostigma; F1 shorter than length of eye; median lobe of mesoscutum shining with sparse punctation; mesoscutellum shining with dense punctation medially, mesepisternum wrinkled in dorsal part and smooth in ventral part; abdomen wider than thorax, with finely alutaceous terga.

Notes on identification. The species has an intermediate appearance between Monsoma pulveratum (Retzius, 1783) (Allantinae) and Sciapteryx consobrina (Klug, 1816) (Tenthredininae) but differs from them by the following characters: clypeus broadly and deeply incised with narrow, sharply pointed lateral lobes; mandibles asymmetric; fore wings with oblique crossvein in anal cell, medial vein fused with radial sector vein at long distance. The Czech specimens of D. ermak agree extremely well with the original description by ZHELOCHOVTSEV (1968).

Larva. Description of the last instar. Head amber yellow with large dark parietal spot; dorsal side of body greyish with whitish irregular longitudinal subdorsal stripe, ground colour of ventral side whitish, annulet 2 and 4 with ring of flat white warts with setae, annulet 1 with black round spot on dorsum medially; annulet 2 laterally above dark spiracle with black round spot; surpedal lobe and hypopleurit with black marks. The last feeding instar moults to glassy grey-yellowish eonymph with obliterated colour pattern.

Recognition. The last instar larva of Dinax ermak differs from the similar larva of D. jakowleffi , by distinct dark pattern on head ( VERZHUTSKII 1981).

Bionomics. Univoltine. Predicted flight period from mid April to mid May; larval period from May to June. Food plant: Spiraea salicifolia L. ( Rosaceae ). The non-feeding eonymph builds a firm cocoon for pupation, in which it can diapause for up to two years.

Distribution. Russia: southern Ural, East Siberia: Magadan ( ZHELOCHOVTSEV 1968); Czech Republic (new record) ( Fig. 21 ).

Figures

Fig. 1. Dinax ermak (Zhelochovtsev, 1968): a – female (dorsal view); b – male (dorsal view); c – female (lateral view); d – last instar larva (dorsal view); e – last instar larva (laterodorsal view); f – eonymph (dorsal view); g – eonymph (laterodorsal view). Scale: 5 mm.

Fig. 21. Known localities of Dinax ermak (Zhelochovtsev, 1968) in the Czech Republic.