Sycophila submutica (Thomson 1876)

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 : 2954-2955

Sycophila submutica (Thomson 1876)

( Figures 1 , 2 , 4E, F , 5E , 6E, F , 7E, F , and 8E )

Description

Body length 2.17 mm (range 1.4–2.7; n = 20); body width 1.27 mm (0.8–1.8) ( Figures 4E, F , and 5E ); body fusiform, broadest in mid-region, tapering anteriorly and posteriorly; ratio L/W = 1.8; ventral margin of body segments clearly convex for specimens reared from galls of Isocolus scabiosae form rogenhoferi, but straight or slightly convex for specimens associated with galls of Isocolus lichtensteini ; anterodorsal protuberances in lateral view absent, the intersegmental membranes not protruding ( Figure 5E ).

Dorsal margin of the vertex convex, ratio SA/DAV = 1.18 ( Figure 6E, F ); anteromedial setae of vertex situated midway between vertex and antenna on the upper face ( Figure 6E ); ventral margin of clypeus distinct; labrum with deep divisions almost reaching the level of labral setae; two lateral flaps and five clearly differentiated lobes with the central part broadest and shorter than lateral ones; maxillae well differentiated, protruding from labium ( Figure 7E, F ).

Mandibles bidentate; for specimens reared from Isocolus scabiosae form rogenhoferi, ratio L/W 1T = 2.4 ( Figure 8E ); second tooth triangular, acute at apex; inner margin of mandible, from the base of second tooth, straight, not interrupted.

Remarks

Despite a drawing of the larva in lateral view being provided by Claridge (1959), it was not described in detail. The larva of S. submutica has some differences according to its hosts as has been stated earlier but generally it is closely related in appearance to the larva of S. biguttata ( Figure 9I ). They differ in the shape of the ventral margin of body, the position and relative separation of the anteromedial setae of vertex, the ventral margin of clypeus and the mandibles.

Biology

Sycophila submutica ( Figure 9J ) is a polyphagous primary endoparasitoid associated with several cynipid galls on herbs. It has been reared from galls of species of Aulacidea , Isocolus , Liposthenes , Phanacis and Rhodus on Asteraceae and Lamiaceae ( Askew et al. 2006) . Larvae of the species are usually found in gall chambers of different species of Isocolus ( Figure 9K ). Specimens for this study were reared from galls of Isocolus lichtensteini (Mayr) ( Figure 9L ) and Isocolus scabiosae (Giraud) form rogenhoferi Wachtl on different species of Centaurea (Asteraceae) .

Material examined

ex Isocolus lichtensteini : Spain, Guadalajara: Pozo de Guadalajara, 3 October 2004, J.L. Nieves leg, (n = 8); Spain, Madrid: Arganda, 6 November 2002, J.L. Nieves leg, (n = 7); ex Isocolus scabiosae form rogenhoferi: Spain, Madrid: Chinchón, 20 September 2003, J.L. Nieves leg (n = 1), 6 June 2004, J.L. Nieves leg, (n = 3); Spain, Madrid: Morata de Tajuña, 6 June 2004, J.L. Nieves and J.F. Gómez leg, (n = 1).

Figures

Figure 1. Body in ventral view of Sycophila submutica (Thomson). Letters refer to the following structures: ABS1–ABS9, abdominal segments; ANS, anal segment; THS1–THS3, thoracic segments.

Figure 2. Body in lateral view of Sycophila submutica (Thomson). Letters refer to the following structures: ABS1–ABS9, abdominal segments; ANS, anal segment; THS1–THS3, thoracic segments; adp, anterodorsal protuberances; epc, spiracles.

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.