Eurytoma aspila (Walker, 1836)

Gómez, José Francisco, Nieves-Aldrey, José Luis, Nieves, María Hernández & Stone, Graham Nicholas, 2011, Comparative morphology and biology of terminalinstar larvae of some Eurytoma (Hymenoptera, Eurytomidae) species parasitoids of gall wasps (Hymenoptera, Cynipidae) in western Europe, Zoosystema 33 (3), pp. 287-323 : 301-302

Eurytoma aspila (Walker, 1836)

MATERIAL EXAMINED. — Ex Aulacidea follioti : France. Pyrénées-Atlantiques, vallée d’Aspe, 7.VIII.2003, J. L. Nieves leg (n = 3).

Ex A. tragopogonis : Spain. Madrid, Arganda, 18.X.2003, J. L. Nieves leg (n = 2). — Dehesa de Arganda, 6.XI.2002, J. L. Nieves leg (n = 22).

Ex P. caulicola : Spain. Orense, Rubiá, 18.VII.2003, J. L. Nieves leg (n = 12, of which 2 specimens MNHN- EY6411).

DESCRIPTION

n = 39; body length 1.5 mm (range 1-2.2); body width 0.8 mm (0.47-1.0) ( Figs 5A ; 7A ; 14A ); body elongate, fusiform, tapering slightly anteriorly and posteriorly; ratio L/W = 2.02; ventral margin of body segments 4-8, in lateral view, clearly convex; anterodorsal protuberances present from the second thoracic to fifth abdominal segment, clearly protruding beyond the dorsal margin of body ( Fig. 7A ).

Antero-medial setae of vertex relatively high on the upper face, close to this margin; ratios SA/DAV = 0.47 and SA/LAA = 0.41 ( Fig. 9A ); dorsal-labral setae as long as clypeal setae; ventral margin of clypeus indistinct, without any discernible suture; divisions on the medial part of labrum deep and almost reaching the level of labral setae, two short lateral flaps and five lobes being visible; maxillary palps conspicuous ( Fig. 11A ).

A pair of symmetrical mandibles present and well developed, their apical teeth completely exposed ( Figs 11A ; 13A ); both mandibles with three teeth, one larger and two shorter with the ratio L/W = 1.61; first tooth short and wide; outer margin of first tooth strongly convex; tip moderately recurved; the shape of apex of the second tooth varies ac- cording to the host from pointed to straight, and is directed upwards in the same direction of the first tooth ( Fig. 13A ).

BIOLOGY

Eurytoma aspila is a polyphagous ectoparasitoid associated with Aylacini gall wasps on herbs.It is usually reared from galls of Aulacidea and Phanacis on different species of Asteraceae . Fully-grown larvae overwinter inside gall cells ( Fig. 14B ), and adults emerge in the spring, in synchrony with cynipid oviposition on the stems and the development of new gall chambers.

REMARKS

The larva of E. aspila is readily separated from the other Eurytoma larvae discussed here by their three-toothed mandibles ( Fig. 13A ).

Figures

FIG. 5.— Ventral views ofterminal-instar eurytomidlarvae:A, Eurytomaaspila (Walker,1836) ex Phanacis caulicola; B, E.brunniventris Ratzeburg, 1852 ex Cynips quercus (A); C, E. cynipsea Boheman, 1836 ex Phanacis hypochoeridis; D, E. infracta Mayr, 1904; E, E. mayri Ashmead, 1887; F, E. pediaspisi Pujade i Villar,1994; G, E. robusta Mayr, 1878; H, E. rosae Nees, 1834 ex Diplolepis rosae. Scale bars:1 mm.

FIG. 7.— Lateralviews ofterminal-instar eurytomidlarvae:A,Eurytoma aspila (Walker,1836) ex Phanacis caulicola; B, E.brunniventris Ratzeburg, 1852 ex Cynips quercus (A); C, E. cynipsea Boheman, 1836 ex Phanacis hypochoeridis; D, E. infracta Mayr, 1904; E, E. mayri Ashmead, 1887; F, E. pediaspisi Pujade i Villar,1994; G, E. robusta Mayr, 1878; H, E. rosae Nees, 1834 ex Diplolepis rosae. Scale bars:1 mm.

FIG. 14. — A, terminal-instar larva of Eurytoma aspila (Walker, 1836) ex gall of Aulacidea tragopogonis; B, larval cells of Phanacis centaureae with terminal-instar larvae of E. aspila; C, cross-section of Cynips quercus (A) leaf gall showing terminal-instar larva of E. brunniventris Ratzeburg, 1852, with debris of adult host; D, ventral view of terminal-instar larva of E. brunniventris ex gall of C. quercus (A);E, cross-section of a gall of Cynips divisa (A) showing fully-grown larva of E. brunniventris; F, terminal-instar larva of E.brunniventris ex gall of Plagiotrochus australis (S);G, anterior view of head of fully-grown larva of E.brunniventris ex gall of P.australis (S); H, larval cells of Aulacidea pilosellae with terminal-instar larva of E. cynipsea Boheman, 1836; I, larval cell on Silybum marianum with terminal-instar larva of E. cynipsea feeding on gall tissue; J, terminal-instar larva of E. robusta Mayr, 1878 in cell of Isocolus leuzeae gall; K, cross-section of Diplolepis centifoliae leaf gall showing terminal-instar larva of E. rosae Nees, 1834; L, lateral view of fully-grown larva of E. rosae ex gall of D. centifoliae.

FIG. 9. — Anterior views of the head of terminal-instar eurytomid larvae: A, Eurytoma aspila (Walker, 1836) ex Phanacis caulicola; B, E. brunniventris Ratzeburg, 1852 ex Cynips quercus (A); C, Eurytoma infracta Mayr, 1904; D, Eurytoma mayri Ashmead, 1887; E, Eurytoma pediaspisi Pujade i Villar, 1994; F, Eurytoma robusta Mayr, 1878. Scale bars: A, B, D, F, 400 μm; C, 300 μm; E, 200 μm.

FIG. 11. — Anterior views of mouthparts of terminal-instar eurytomidae larvae:A, Eurytoma aspila (Walker,1836) ex Phanacis caulicola; B, E. brunniventris Ratzeburg, 1852 ex Cynips quercus (A); C, E. cynipsea Boheman, 1836 ex Phanacis hypochoeridis; D, E. infracta Mayr, 1904; E, E. mayri Ashmead, 1887; F, E. pediaspisi Pujade i Villar, 1994. Scale bars: A, E, 200 μm; B-D, F, 100 μm.

FIG. 13.— Anterior views of the right mandible of terminal-instar eurytomid larvae:A, Eurytoma aspila (Walker,1836) ex Phanacis caulicola; B, E. brunniventris Ratzeburg, 1852 ex Cynips quercus (A); C, E. cynipsea Boheman, 1836 ex Phanacis hypochoeridis; D, E. infracta Mayr, 1904; E, E. mayri Ashmead, 1887; F, E. pediaspisi Pujade i Villar, 1994; G, E. robusta Mayr, 1878; H, E. rosae Nees, 1834 ex Diplolepis rosae; I, E. rufipes Walker, 1832; J, E. sp. cf. aspila; K, E. sp. cf. jaceae; L, E. strigifrons Thomson, 1876 (right mandible); M, E. strigifrons (left mandible); N, E. timaspidis (Mayr, 1904). Scales bars: A, D-G, I-N, 50 μm; B, 20 μm; C, H, 100 μm.