Ormyrus pomaceus (Geoffroy, 1785)

Gomez, Jose F., Nieves, Maria Hernandez, Gayubo, Severiano F. & Nieves-Aldrey, Jose Luis, 2017, Terminal-instar larval systematics and biology of west European species of Ormyridae associated with insect galls (Hymenoptera, Chalcidoidea), ZooKeys 644, pp. 51-88 : 66-69

Ormyrus pomaceus (Geoffroy, 1785)

Material examined.

ex gall Andricus grossulariae asex. on Quercus faginea , Spain, Cádiz: La Suara-Jérez, 16.X.04, J. L. Nieves leg. (n = 1); ex gall Plagiotrochus fusifex on Quercus coccifera , Spain, Madrid: Arganda, 01.VI.03, J. L. Nieves leg. (n = 1); ex gall Plagiotrochus razeti on Quercus ilex , Spain, Madrid: Villanueva del Pardillo, 07/X/02, J. L. Nieves leg. (n = 11). ex gall Trigonaspis mendesi on Quercus faginea , Spain, Madrid: Boadilla del Monte, 23/IX/02, J. L. Nieves leg. (n = 1).

Description.

Ex gall Andricus grossulariae asex., on Quercus faginea , n = 1; Body length: 2.73 mm, width: 1.67 mm; ex gall Plagiotrochus fusifex on Quercus coccifera , n = 1; Body length: 1.13 mm, width: 0.53 mm; ex gall Plagiotrochus razeti on Quercus ilex , n = 11; Body length: 2.21 ± 0.46 mm (min-max: 1.80-3.40 mm), width: 1.10 ± 0.10 mm (min-max: 0.93-1.27 mm); ex gall Trigonaspis mendesi on Quercus faginea , n = 1; Body length: 1.55 mm, width: 0.80 mm.

The morphology of the terminal larva of this species is very similar to that of the Ormyrus nitidulus larva. The larvae of Ormyrus pomaceus from galls of Andricus and Trigonaspis species were distinguished from those of Ormyrus nitidulus by the following characters: integument of thoracic and abdominal segments with conspicuous blister-like sculpture; distance among vertex setae longer than the distance between antennae; am 0.47 as long as the distance between antennae; lcs situated above the level of cs, being separated from cs by 1.2-fold the distance between cs; and maxillary palps not visible (Table 2).

For the Ormyrus pomaceus larvae that inhabited Plagiotrochus galls (Figs 4C, 6B, 8C, and 10A), the differences between Ormyrus pomaceus ex Andricus and ex other host genera, such as Trigonaspis (Figs 4B, 6A, 8B, and 9H), were the following: am shorter in length than the separation between antennae (Table 2) and maxillary palps conspicuous.

Biology.

Ormyrus pomaceus is a polyphagous ectoparasitoid that attacks more than 56 different cynipid galls on Quercus trees (Figs 14F and I; 15D and E) ( Askew et al. 2013). Nevertheless, results from ongoing unpublished molecular studies clearly indicate that Ormyrus pomaceus includes a complex of sibling or cryptic species that are segregated according to cynipid hosts, host plant species and ecological preferences (Hernandez Nieves et al. unpublished, Stone pers. comm.). On the Iberian Peninsula, among the most regular host species of Ormyrus pomaceus , we found the asexual generations of Andricus grossulariae (Fig. 14D and E) and Andricus pictus (Fig. 14G and H), Trigonaspis mendesi (Fig. 14J and K) and Trigonaspis brunneicornis (Figs 14L and 15A) on Quercus pyrenaica and Quercus faginea and the galls of asexual species of Plagiotrochus on Quercus ilex and Quercus coccifera (Fig. 15B and C).