Sycophila biguttata (Swederus 1795)

Gómez, J. F., Nieves-Aldrey, J. L. & Stone, G. N., 2013, On the morphology of the terminal-instar larvae of some European species of Sycophila (Hymenoptera: Eurytomidae) parasitoids of gall wasps (Hymenoptera: Cynipidae), Journal of Natural History 47 (47 - 48), pp. 2937-2960 : 2950-2951

Sycophila biguttata (Swederus 1795)

( Figures 3B , 4A , 5A , 6A , 7A , and 8A )

Description

Body length 3.24 mm (range 2.9–3.9; n = 3); body width 1.88 mm (1.5–2.13) ( Figures 4A and 5A ); body fusiform and broadest in mid-region, tapering anteriorly and posteriorly; ratio L/W = 2.07; ventral margin of body segments 4–8 in lateral view clearly convex; anterodorsal protuberances absent, the intersegmental membranes not protruding.

Dorsal margin of the vertex straight or slightly concave; ratio SA/DAV = 1.13; anteromedial setae of vertex situated midway between anterior margin of vertex and the antennae; ventral margin of clypeus indistinct ( Figure 6A ); labrum with deep divisions almost reaching the level of labral setae, with one or two pairs of lateral flaps and a medial part divided into five differentiated lobes; maxillae well-differentiated from labium; maxillary palps invisible ( Figure 7A ).

Mandibles with two teeth ( Figure 8A ); ratio L/W 1T = 2; second tooth relatively small and short, triangular; apex of the second tooth acute; inner margin of mandible from the base of second tooth straight, not interrupted.

Remarks

Larvae of S. biguttata resemble the larvae of S. submutica and S. binotata in their fusiform body shape, but differ from them in the shape of the ventral margin of body segments, the dorsal margin of the vertex, the ventral margin of clypeus, the ratio of length/width of the first tooth and the apex of the second tooth principally.

Biology

The species Sycophila biguttata is a polyphagous endoparasitoid reared from different gall wasp species on oaks ( Quercus ) and chestnuts ( Castanea ) ( Fagaceae ) ( Claridge 1959; Askew 1961; Aebi et al. 2006) ( Figure 9A B ). Sycophila biguttata constitutes a complex of which the nomenclature and separation into discrete entities has been recently updated ( Lotfalizadeh et al. 2008). Specimens for this study were reared from asexual generation galls of Andricus quercustozae (Bosc) on Quercus faginea (L.) ( Fagaceae ) ( Figure 9C ).

Material examined

ex Andricus quercustozae (asex.): Spain, Ciudad Real : Despeñaperros, 15 October 2004, J.L. Nieves leg, (n = 3) .

Figures

Figure 3. Illustrations of the terminology used for general descriptions in different views. (A) Anterior view of head of Sycophila mayri (Erdos), letters refer as follows to the described structures: ams, anteromedial setae of antennal region; an, antenna; anr, antennal area; cl, clypeus; cs, clypeal setae; fr, frons; gns, genal setae; gr, genal region; hr, hypostomal region; hs, hypostomal setae; lb, labrum; lbi, labium; md, mandible; mx, maxillae; vams, anteromedial setae of vertex; vr, vertex region. (B) Anterior view of mouthparts of Sycophila biguttata (Swederus), showing the clypeus (cl); clypeal setae (cs); labrum (lb); labral setae (lbs); lateral lobes of labrum (lfp): medial piece of labrum (lmp) and the lower-lip complex: labium (lbi); mandible (md); maxillae (mx). (C) Anterior view of the right mandible of Sycophila binotata (Fonscolombe), showing the first and second tooth and the base (mbs).

Figure 4. Ventral views of terminal-instar larvae. (A) Sycophila biguttata; (B) Sycophila binotata; (C) Sycophila flavicollis; (D) Sycophila mayri; (E) Sycophila submutica ex Isocolus scabiosae form rogenhoferi; (F) Sycophila submutica ex Isocolus lichtensteini.

Figure 5. Lateral views of terminal-instar larvae. (A) Sycophila biguttata; (B) Sycophila binotata; (C) Sycophila flavicollis; (D) Sycophila mayri; (E) Sycophila submutica ex Isocolus scabiosae form rogenhoferi

Figure 6. Anterior view of the head of terminal-instar larvae. (A) Sycophila biguttata; (B) Sycophila binotata; (C) Sycophila flavicollis; (D) Sycophila mayri; (E) Sycophila submutica ex Isocolus. scabiosae form rogenhoferi; (F). Sycophila submutica ex Isocolus lichtensteini.

Figure 7. Anterior view of mouthparts of terminal-instar larvae. (A) Sycophila biguttata; (B) Sycophila binotata; (C) Sycophila flavicollis; (D) Sycophila mayri; (E) Sycophila submutica ex Isocolus scabiosae form rogenhoferi.; (F) Sycophila submutica ex Isocolus lichtensteini.

Figure 8. Anterior view of the right mandible of terminal-instar larvae. (A) Sycophila biguttata; (B) Sycophila binotata; (C). Sycophila flavicollis; (D) Sycophila mayri; (E) Sycophila submutica ex Isocolus scabiosae (k) form rogenhoferi (k).

Figure 9. (A) Cross-section of gall of Andricus grossulariae showing chamber with fully-grown larvae of Sycophila biguttata; (B) habitus of Sycophila biguttata, adult female; (C) fresh galls of asexual generation of Andricus quercustozae on Quercus faginea.; (D) habitus of Sycophila binotata, adult female; (E) galls of asexual generation of Plagiotrochus gallaeramulorum on Quercus coccifera.; (F) cross-section of sexual gall of Andricus quercuradicis on Quercus faginea; (G) habitus of Sycophila mayri, adult female; (H) cross-section of Phanacis centaureae galls on stems of Centaurea spp.; (I) head and mandibles view of fully grown larva of Sycophila submutica ex gall of Isocolus lichtensteini; (J) habitus of Sycophila submutica, adult female; (K) larval cell of Isocolus lichtensteini with terminal-instar larvae of S. submutica; (L) fresh gall of Isocolus lichtensteini on Centaurea aspera.