Cecidostiba geganius ( Walker, 1848 )

Gómez, Jose F. & Nieves-Aldrey, Jose Luis, 2012, Notes on the larval morphology of Pteromalidae (Hymenoptera: Chalcidoidea) species parasitoids of gall wasps (Hymenoptera: Cynipidae) in Europe, Zootaxa 3189, pp. 39-55 : 51

Cecidostiba geganius ( Walker, 1848)

Measurements. Body length: 1.20–3.04 (2.21) mm, maximum width: 0.48–1.12 (0.82) mm (n=43) ex gall A. quercusradicis (Agamic generation).

Description. larger than C. fungosa ; body almost 2.5× as long as broad ( Fig. 4 C) and slightly curved ventrally in lateral view ( Fig. 5 C); ventral margin of body segments convex.

Head (anterior view) regularly rounded, almost as broad as long; vertex clearly incised medially ( Fig. 6 C); ventral margin of clypeus straight; labium more or less semicircular, 4× wider than long ( Fig. 7 C).

Mouth parts ( Fig. 7 C). Maxillae differentiated from labium; two pairs of maxillary palps visible with two pairs of very short setae; labium semicircular, convex and not collapsed, with a pair of inconspicuous setae.

Biology. The species C. geganius is a specific parasitoid of the agamic generation of A. quercusradicis , which induces subterranean galls on roots and stolons of several species of Quercus in Europe ( Fig. 9 F). The larvae of this species are gregarious, many parasitoid larvae being found in a single cell of the multilocular host gall.

Material examined. ex gall A. quercusradicis (Agamic generation) on Quercus faginea , Spain, Madrid: Villaviciosa de Odón (El Bosque) (n=43).

Figures

FIGURE 4. Ventral view of terminal instar pteromalid larvae (A = agamic generation; S = sexual generation for host). A. Arthrolytus glandium ex Callirhytis rufescens (A). B. Cecidostiba fungosa ex Andricus quercusradicis (S). C. Cecidostiba geganius ex Andricus quercusradicis (A). – D. Pteromalus bedeguaris ex Diplolepis rosae. E. Pteromalus hieracii ex Aulacidea follioti. F. Pteromalus isarchus ex Xestophanes potentillae. G. Rivasia fumariae ex Neaylax versicolor. H. Stinoplus lapsanae ex Timaspis lapsanae.

FIGURE 5. Lateral view of terminal instar pteromalid larvae (A = agamic generation; S = sexual generation for host). A. Arthrolytus glandium ex Callirhytis rufescens (A). B. Cecidostiba fungosa ex Andricus quercusradicis (S). C. Cecidostiba geganius ex Andricus quercusradicis (A). D. Pteromalus bedeguaris ex Diplolepis rosae. E. Pteromalus hieracii ex Aulacidea follioti. F. Pteromalus isarchus ex Xestophanes potentillae. G. Rivasia fumariae ex Neaylax versicolor. H. Stinoplus lapsanae ex Timaspis lapsanae.

FIGURE 6. Anterior view of the head of terminal instar pteromalid larvae (A = agamic generation; S = sexual generation for host). A. Arthrolytus glandium ex Callirhytis rufescens (A). B. Cecidostiba fungosa ex Andricus quercusradicis (S). C. Cecidostiba geganius ex Andricus quercusradicis (A). D. Pteromalus bedeguaris ex Diplolepis rosae. E. Pteromalus hieracii ex Aulacidea follioti. F. Pteromalus isarchus ex Xestophanes potentillae. G. Rivasia fumariae ex Neaylax versicolor. H. Stinoplus lapsanae ex Timaspis lapsanae.

FIGURE 7. Anterior view of mouthparts of terminal instar pteromalid larvae (A = agamic generation; S = sexual generation for host). A. Arthrolytus glandium ex Callirhytis rufescens (A). B. Cecidostiba fungosa ex Andricus quercusradicis (S). C. Cecidostiba geganius ex Andricus quercusradicis (A). D. Pteromalus bedeguaris ex Diplolepis rosae. E. Pteromalus hieracii ex Aulacidea follioti. F. Pteromalus isarchus ex Xestophanes potentillae. G. Rivasia fumariae ex Neaylax versicolor. H. Stinoplus lapsanae ex Timaspis lapsanae.

FIGURE 9. A. Larval cell of of Callirhytis rufescens (Agamic generation) with terminal-instar larvae of Arthrolytus glandium. B. Galls of Aulacidea hieracii on Hieracium spp. C. Galls of Xestophanes potentillae on runners of Potentilla reptans. D. Old galls of Callirhytis glandium (Agamic generation). E. Lateral habitus of Cecidostiba fungosa, adult female. F. Galls of Andricus quercusradicis (Agamic generation) on Quercus pyrenaica. G. Cross-section of unilocular gall of Neaylax versicolor showing fully-grown larva of Rivasia fumariae. H. Fresh galls of Diplolepis rosae on Rosa spp. shrub. I. Lateral habitus of Pteromalus bedeguaris, adult female. J. Galls of Timaspis lapsanae on Lapsana communis. K. Terminal instar larva of Stinoplus lapsanae ex gall of Timaspis lapsanae.