Sycophila mayri (Erdös 1959)

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 : 2953-2954

Sycophila mayri (Erdös 1959)

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

Description

Body length 1.7 mm (range 1.3–2; n = 7); body width 0.8 mm (0.7–1.0) ( Figures 4D and 5D ); body barrel-shaped, slightly depressed and tapering anteriorly and posteriorly with lateral margins of abdominal segments 1–6 almost straight; ratio L/W = 2.1; ventral margin of body segments 4–8 in lateral view slightly convex; anterodorsal protuberances absent, with the intersegmental membranes not protruding in the specimens reared from galls on Centaurea scabiosa , whereas in those reared from galls on Centaurea spp. they are present, with the intersegmental membranes of abdominal segments 1–6 slightly protruding ( Figure 5D ).

Dorsal margin of the vertex straight or slightly concave; ratio SA/DAV = 1.35; anteromedial setae of vertex situated relatively high on the upper face; ventral margin of clypeus distinct for specimens reared from galls on C. scabiosa , whereas it is indistinct for those associated with galls on Centaurea spp. ( Figure 6D ); labrum with deep divisions reaching the level of labral setae, divided into two lateral flaps and five medial lobes, resulting in seven clearly differentiated and equal divisions; maxillae well differentiated from labium ( Figure 7D ).

Mandibles bidentate; for specimens reared from galls of Centaurea spp. , ratio L/W 1T = 2.2 ( Figure 8D ); second tooth triangular, acute at apex; inner margin of mandible, from the base of second tooth, straight, continuous.

Remarks

Specimens reared from different host plants have different descriptions as mentioned above. The rest of the characters are convergent in both S. mayri studied. Otherwise the species is similar to the larvae of S. flavicollis in the elongated shape of the body, but readily distinguished from the latter by a different anteromedial setal position on the head and its acute second mandibular tooth.

Biology

The species S. mayri is a polyphagous primary endoparasitoid associated with cynipid galls on herbs ( Figure 9G ). It has been reared from galls of Aulacidea and Phanacis on Asteraceae ( Askew et al. 2006) . Specimens for this study were reared from galls of Phanacis centaureae Foerster , on stems of different Centaurea scabiosa L. and Centaurea spp. (Asteraceae) ( Figure 9H ).

Material examined

ex Phanacis centaureae : on Centaurea scabiosa , Spain, Cuenca: Uña, 2 July 2002, J.L. Nieves leg, (n = 4); on Centaurea spp. , Spain, Madrid: Dehesa de Moncalvillo, 21 April 2005, J.L. Nieves and J.F. Gómez 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.