Eurytoma rosae Nees, 1834

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 : 312-313

Eurytoma rosae Nees, 1834

MATERIAL EXAMINED. — Ex Diplolepis nervosa / D. eglanteriae : Spain. Guadalajara, Hayedo de Tejera Negra, 24.VII.2005, J. L. Nieves leg (n = 3). — Madrid, El Escorial, 13.XI.2002, J. L. Nieves leg (n = 3). Ex D. mayri : Spain. Guadalajara, Retiendas, 24.I.2004, J. L. Nieves leg (n = 22, of which 2 specimens MNHN- EY 6416). — Madrid, Cotos de Monterrey, 24. VI.2003, J. F. Gómez leg (n = 31). — Same locality, 9.VIII.2002, J. L. Nieves leg (n = 3). — Soria, Cabrejas del Pinar, 14-15. II.04, J. F. Gómez leg (n = 5). — Soria, Embalse de la Cuerda del Pozo, 15.II.2004, J. F. Gómez leg (n = 4). Ex D. rosae : Spain. Guadalajara, Retiendas, 24.I.2004, J. L. Nieves leg (n = 1). — Madrid, El Escorial-La Herrería, 4.II.2004, J. F. Gómez leg (n = 2). — Soria, Cabrejas del Pinar, 14-15.II.2004, J. F. Gómez leg (n = 1). — León, San Esteban, 16.VII.2005, J. F. Gómez leg (n = 3).

DESCRIPTION

n = 78; body length 2 mm (range 1.3-3.5); body width 0.81 mm (0.5-1.33) ( Figs 5H ; 7H ; 14L ); body fusiform, elongated, slightly tapering anteriorly and a little more posteriorly; ratio L/W = 2.92; ventral margin of body segments convex; anterodorsal protuberances present from second thoracic segment to the tenth abdominal, protruding beyond the dorsal margin of body segments ( Fig. 7H ).

Antero-medial setae of the antennal area situated clearly below the antennae; ratio SA/LAA = 0.67; separation of antero-medial setae of vertex equal to the distance between antennae and with these setae situated relatively high on the upper face, closer to the anterior margin of vertex than to the antennae ( Fig. 10A ); dorsal-labral setae longer than clypeal setae; ventral margin of clypeus with a distinct suture; labrum with a pair of short lateral flaps and a medial part with deep divisions defining five ir- regular but clearly differentiated lobes; maxillary palps inconspicuous ( Fig. 12B ).

Mandibles with two teeth; apical tooth completely visible ( Fig. 12B ); ratio L/W 1T = 1.36; outer margin of first tooth strongly convex, with the tip moderately recurved; apex of the second tooth moderately recurved inwards and more or less acute; inner margin of mandible from the base of second tooth more or less straight, with the margin not interrupted ( Fig. 13H ).

BIOLOGY

The larva of this species preferentially attacks the cells of the inquiline species Periclistus brandtii (Ratzeburg, 1831) and P. caninae (Hartig, 1840) , and our unpublished molecular data confirm that the same species also attacks inquilines in oak cynipid galls. According to Nordlander (1973) and Redfern & Askew (1992) the larva of E. rosae feeds on more than one Periclistus larva by biting its way from one chamber to another, and thus in a strict sense, the larva should be referred as a predator rather than a parasitoid.In Spain, we found larvae of E. rosae to be predominantly associated with D. mayri galls containing cells of P. brandtii and with D. nervosa galls occupied by P. caninae ( Fig. 14K ). In both cases the mature parasitoid larva fed on the lining of the host larval chamber, as shown by the presence of chips of plant tissue adhering to the larval body of E. rosae and the deformation of the original inquiline larval cell ( Figs 14K ; 15A ). Lotfalizadeh et al. (2007b) have recently carried out a review of the species based on adult morphology and molecular data describing a new species, E. caninae Lotfalizadeh, Delvare & Rasplus, 2007 previously overlooked with E. rosae . Both species are reared from galls of Diplolepis in Palaearctic area although in our study E. caninae have not been considered.

REMARKS

The moderately inwards recurved shape of the second mandible tooth readily separates the larva of E. rosae from the larva of E. brunniventris , two species that, according to Claridge & Askew (1960), are otherwise undistinguishable on the basis of adult morphology.

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. 10. — Anterior views of the head of terminal-instar eurytomid larvae:A, Eurytoma rosae Nees,1834 ex Diplolepis rosae; B, E. rufipes Walker, 1832; C, E. sp. cf. aspila; D, E. sp. cf. jaceae; E, E. strigifrons Thomson, 1876; F, E. timaspidis (Mayr, 1904). Scale bars: A-C, 300 μm; D, 200 μm; E, F, 400 μm.

FIG. 12. — Anterior views of mouthparts of terminal-instar eurytomidae larvae:A, Eurytoma robusta Mayr,1878; B, E. rosae Nees,1834 ex Diplolepis rosae; C, E. rufipes Walker,1832;D, E.sp.cf.aspila; E, E. sp. cf. jaceae; F, E.strigifrons Thomson,1876; G, E.timaspidis (Mayr, 1904). Scale bars: A-E, 100 μm; F, G: 200 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.

FIG. 15. — A, section of a gall of Diplolepis mayri showing a fully-grown larva of Eurytoma rosae Nees, 1834; B, cross-section of Xestophanes brevitarsis (Thomson,1877) gall showing fully-grown larva of E. rufipes Walker, 1832 with host larva; C, cross-section of old gall of Aulacidea subterminalis Niblett, 1946 showing fully-grown larva of E. sp. cf. aspila; D, detail of mandibles of E. sp.cf. aspila ex gall of A. subterminalis; E, lateral view of terminal-instar larva of E. strigifrons Thomson,1876 ex gall of Isocolus lichtensteini (Mayr, 1882); F, cross-section of fresh gall of Timaspis phoenixopodos Mayr, 1882 showing fully-grown larvae of E. timaspidis (Mayr, 1904); G, larval cell of T. phoenixopodos with terminal-instar larvae of E. timaspidis.