Eutomostethus luteiventris (Klug, 1816)

Macek, Jan, 2014, Descriptions of larvae of the Central European Eutomostethus species (Hymenoptera: Symphyta: Tenthredinidae), Acta Entomologica Musei Nationalis Pragae 54 (2), pp. 685-692 : 689

Eutomostethus luteiventris (Klug, 1816)

( Figs 2 , 8 )

Material examined. CZECH REPUBLIC: BOHEMIA BOR.: Louny distr., Brodec (5748), 4.viii.2012, larvae on Juncus effusus . BOHEMIA CENTR.: KĜivoklátsko PLA, Prameny Klíþavy NR (5848), 12.vii.2010, larvae on Juncus effusus . All J. Macek lgt. & det. ( NMPC).

Redescription of the last instar larva. Body length 12–14 mm. Head amber yellow with blackish strip alongside coronal suture, head surface granulose, in upper half with scattered tiny setae and a row of longer setae alongside epistomal suture; clypeus with six setae, labrum symmetrical, deeply emarginated anteriorly with eight setae, mandibles with one seta, palpifer with three setae, maxillar palpus with one seta, stipes with one seta; body slender, slightly tapered caudally; body in upper part grey-yellowish, in lower part paler with dark dorsal and subspiracular longitudinal stripes; pale spiracles placed in whitish line bordering the dark supraspiracular strip; cuticle ¿nely granulose; trochanter as long as femur, with scattered long hair-like setae, third abdominal segment with six annulets; second and fourth annulets, subspiracular and surpedal lobes, and anal segment with several very tiny, and inconspicuous, blunt setae, fourth annulet with two or four conical glandubae, ¿rst and second postspiracular lobes with one glanduba each; anal segment with six glandubae alongside posterior margin; suranal lobe with a row of tough setae on posterior margin.

Notes on identification. Compared to the similar larvae of E. punctatus and E. gagathinus , those of E. luteiventris differ in the surface sculpture of the anal segment (see Fig. 2a ).

Bionomics. Habitat: humid meadows, marshes, fens, shore vegetation alongside pools, brooks and rivers from planar to montane zone; univoltine, occasionally bivoltine ( WEIFFENBACH 1985), flight period mid May to the end of June (occasionally also from July to August); larval period from July to August. Host plants: Juncus effusus , J. conglomeratus ( LISTON 1997, PSCHORN- WALCHER & ALTENHOFER 2000). I swept larvae on Juncus effusus beside the shore of the pool on the forest path near Louny, and in Prameny Klíþavy NR in August (see Material examined). The female oviposits into young sterile shoots of the food plant. The larva starts mining upwards in the pulp, until the last larval instar, then feeds externally on young shoots of the host plant. The infested stems turn yellow and become very fragile. The larva hibernates at prepupal stage in the soil, in an earthen cell ( CONDE 1934, KONTUNIEMI 1960).

Discussion. The larval development with the description of larvae is given by CONDE (1934), and additional characters by LORENZ & KRAUS (1957). The purpose of the present redescription provided here is completeness, so it could be easy compared with the descriptions of the larvae of the other Eutomostethus species.

Figures

Figs 1–4. Mounted larvae from alcohol. 1 – Eutomostethus ephippium (Panzer, 1798); 2 – E. luteiventris (Klug, 1816); 3 – E. punctatus (Konow, 1887); 4 – E. gagathinus (Klug, 1816). Lettering: a – the cuticular sculpture of the anal segement; b – the prothorax, the arrow indicating the protuberant suprapedal lobe. Scale bar: 2 mm.

Figs 5–8. Living last instar larvae (a – lateral view; b – dorsal view). 5 – Eutomostethus gagathinus (Klug, 1816); 6 – E. ephippium (Panzer, 1798); 7 – E. punctatus (Konow, 1887); 8 – E. luteiventris (Klug, 1816). Scale bar: 5 mm.