Dineura stilata ( Klug, 1816 )

Macek, Jan, 2015, Descriptions and key to larvae of Central European Dineura (Hymenoptera: Symphyta: Tenthredinidae), Acta Entomologica Musei Nationalis Pragae 55 (2), pp. 787-796 : 791-792

Dineura stilata ( Klug, 1816)

( Figs 1 , 4 , 7 )

Tenthredo (Allantus) stilata Klug, 1816: 82–83 (original description). Dineura stilata: HARTIG (1837: 227) , TAEGER et al. (1998).

Material examined. CZECH REPUBLIC: BOHEMIA CENTR.: Praha – Černý Most (5953), 3.x.2004, 26 larvae on Crataegus sp .; Praha – Hlubočepy (5952), 12.ix.2013, 3 larvae on Crataegus sp .; all J. Macek lgt. & det. ( NMPC) .

Description of the last instar larva. Body length 7–10 mm. Colour. Head amber yellow, trunk green excluding whitish last two annulets of each abdominal segment and dark transparent dorsal vessel; spiracles white.

Morphology. Head orthognathous with long, slightly curved, stiff, trichoid setae; upper part of head with darker reticulate texture; labrum symmetrical, with straight anterior margin; labrum and clypeus with four setae; stipes with one seta; palpifer with two setae.

Trunk dorsoventrally flattened with thorax distinctly broader than abdomen; subspiracular lobe of second and third thoracic segments enlarged and prominent, bearing short truncate setae; trochanter as long as femur; femur with two setae; tibiae with 6 setae; abdominal segments with six annulets; first, second and fourth annulets with simple and paired, short, truncate setae placed on inconspicuous flat warts; length of setae is shorter than width of the annulet; postspiracular lobes prominent, the first one with two paired truncate setae, the second one with two truncate setae; subspiracular lobe with three trichoid setae and one glanduba; suprapedal lobe with four trichoid setae; anal segment with scattered long trichoid setae; prolegs on inner side with two to three tiny trichoid setae.

Differential diagnosis. Compared to the D. testaceipes , the larvae of D. stilata are easily distinguished by the short and truncate setae, placed on flat, inconspicuous warts (see the Key above).

Bionomics. Univoltine; flight period from May to July; larval period from July to October. Food plant: Crataegus sp. (new record). Based on the recent collecting data the species prefers the xeric shrubby habitats (shrubby forest margins, shrubby meadows, and shrubby steppes) with hawthorn stands.

Discussion. Due to the difficulties with identification of adults of D. stilata and D. testaceipes , the larvae of these species has not been properly recognized before. The first description of the larva of D. stilata by BRISCHKE’ s (1883) refers without doubt to D. testaceipes . The same is true for the characterisations of D. stilata larvae given by LORENZ & KRAUS (1957) and VERZHUTSKII (1981). Accordingly, the larva of D. stilata actually remained unknown. The current study, based on field collections and rearing larvae to the adult stage enabled me to correctly associate both larval morphotypes with the corresponding adults.

Figures

Figs 1–3. Dineura Dahlbom, 1835, adults: 1 – D. stilata (Klug, 1816), 2 – D. testaceipes (Klug, 1816), 3 – D. virididorsata (Retzius, 1783). Scale bar: 5 mm.

Figs 4–6. Dineura Dahlbom, 1835, larvae (a – lateral view, b – dorsal view): 4 – D. stilata (Klug, 1816), 5 – D. testaceipes (Klug, 1816), 6 – D. virididorsata (Retzius, 1783). Scale bar: 10 mm.

Figs 7–8. Dineura Dahlbom, 1835, 3rd abdominal segment of larvae (a – dorsal section, b – subspiracular lobe): 7 – D. stilata (Klug, 1816), 8 – D. testaceipes (Klug, 1816), 9 – D.virididorsata (Retzius, 1783). Scale bar: 0.05 mm.