Eurytoma melanoneura, WALKER, 1871

Delvare, Gérard, Gebiola, Marco, Zeiri, Asma & Garonna, A. P., 2014, Revision and phylogeny of the European species of the Eurytoma morio species group (Hymenoptera: Eurytomidae), parasitoids of bark and wood boring beetles, Zoological Journal of the Linnean Society 171 (2), pp. 370-421 : 400-401

EURYTOMA MELANONEURA WALKER, 1871

( FIG. 29A–D )

Eurytoma melanoneura Walker, 1871: 14 . Original description ♀. UK: Barnstaple. Graham, 1970: 151. Lectotype designation.

Eurytoma morio Boheman : Graham, 1970: 151 (erroneous synonymy).

Type material

Lectotype ♀, designated by Graham ( BMNH type 5- 570 ). The type, examined in 2005 by G.D., was found to differ from the specimens of E. morio identified by Graham and Boucˇek in the BMNH collection. The interpretation of this last species is confirmed here as being correct, but the identity of E. melanoneura must be re-assessed as the molecular data analysed by us showed that two species were mixed in our initial sorting. According to the iterative process described in ‘Material and methods’ it was possible to find some characters separating the apparent cryptic species of this pair. Illustrations of the relevant characters were provided to Andrew Polaszek ( BMNH), together with some comments, allowing him to assign one of the species to the lectotype of E. melanoneura .

Diagnosis

The species is similar to E. striolata ; therefore, only differential characters are reported here. The marginal vein is relatively long, 4.85 times as long as wide, not widening distally. The lower surface of the costal cell has a narrow posterior bare stripe (visible only when the wing is tilted); the setation is somewhat longer and sparser than in E. striolata , and often dark. Otherwise, all other characters are identical. Furthermore, this species together with E. striolata exhibit considerable intraspecific phenotypic variation linked with the size of the specimens. The direction of the changes, being identical with E. striolata , is described below for that species. The smallest specimens, belonging to the minor form, are especially difficult to separate from E. striolata because their differential characters are attenuated.

Hosts

Eurytoma melanoneura is most often collected on logs and dying deciduous trees. Our rearing nevertheless included Tomicus destruens (Wollaston, 1865) and Orthotomicus erosus (Wollaston, 1857) on Pinus pinea L. 1753, Tomicus minor on Pinus nigra ssp. salzmannii var. corsicana (= P. nigra ssp. laricio ) and second instar larvae of Anoplophora chinensis (Forster, 1771) (Cerambycidae) under bark of Salix alba (used as sentinels).

Distribution

Eurytoma melanoneura is relatively common and widely distributed. The specimens examined came from the UK, France, Italy, including Sardinia, Slovenia, and Poland (see Appendix S4 and Fig. S7 of Appendix S8).

Figures

Figures 7. A–F, measurements of adult Eurytoma. Head and antenna: A, head in dorsal view; B, vertex; C, female antenna; D, male antenna; E, head in ventral view; F, head in frontal view. Abbreviations listed in Appendix S5.

Figure 29. A–H, comparison between Eurytoma melanoneura and Eurytoma striolata (♀ major forms): A–D, E. melanoneura; E–H, E. striolata. A, E, base of forewing; B, F, same, wing tilted to see the bare posterior stripe of the basal cell; C, G, detail of setation of the costal cell; D, H, apical venation.