Fidiobia hispanica Popovici & Buhl, 2010

Notton, David G., Popovici, Ovidiu A., Achterberg, Cornelis Van, Rond, Jeroen De & Burn, John T., 2014, Parasitoid wasps new to Britain (Hymenoptera: Platygastridae, Eurytomidae, Braconidae & Bethylidae), European Journal of Taxonomy 99 (99), pp. 1-20 : 2-4

Fidiobia hispanica Popovici & Buhl, 2010

Figs 1-3

Fidobia synergorum – O’Connor et al., 2004: 14 [not Kieffer, 1921] [misidentification].

Identification

Specimens were identified to genus using the key by Masner & Huggert (1989) and to species with the key by Popovici & Buhl (2010). Detailed illustrations are given by Popovici & Buhl (2010). The following notes are provided to improve the diagnosis of the female metasoma given in the original description of this species and to take account of telescoping of the apical gastral tergites, which varies naturally and can also be affected by the preservation techniques used. Numbers given are: range (arithmetic mean, ± standard deviation) {range for the type series}.

Diagnosis of female metasoma

Ratio between length and width of metasoma 2.1–2.7 (2.2 ±0.17) {2.7–2.8}; ratio between width and length of T1 3.0–4.5 (3.4 ±0.5) {3.6–5.0}; ratio between maximum and minimum width of T1 1.1–1.7 (1.4 ±0.16) {1.5–1.7}; ratio between length and width of T2 0.8–1.1 (0.9 ±0.1) {1.0}; ratio between length of T2 and length of T1 3.3–6.5 (4.1 ±0.9) {4.8–5.0}; ratio between length of T2 and length of T3 3.1–4.0 (3.6 ±0.3) {2.4}; ratio between maximum and minimum width of T2 1.2–1.5 (1.3 ±0.1) {1.2– 1.3}; ratio between length of T3 and length of T4 1–1.5 (1.1 ±0.2) {1.0–1.3}; ratio between maximum and minimum width of T3 1.1–1.3 (1.2 ±0.1) {1.1}; ratio between maximum and minimum width of T4 1.1– 1.6 (1.2 ±0.1) {1.1–1.3}; T6 triangular, ratio between length of T6 and T5 1.7–2.8 (2.1 ±0.4) {1.3–1.5}.

Material examined

ENGLAND: London, Greenwich, Vanbrugh Pits, 16 ♀♀, 3 ♂♂, reared from a batch of beetle eggs in vacated Andricus lignicola (Hartig, 1840) gall on Quercus robur Linnaeus, 1753 , gall collected 17 Jan. 2010, D. G. Notton; London, Greenwich, Vanbrugh Pits, TQ397771, 5 ♀♀, reared from a batch of beetle eggs in a vacated cell of Synergus umbraculus (Olivier, 1791) in an old Andricus kollari (Hartig, 1843) gall on Quercus robur , gall collected 14 Mar. 2010, D. G. Notton (all BMNH).

Distribution

Genus and species recorded here as new to Britain. Previously recorded from Ireland by O’Connor et al. (2004, as F. synergorum ) and from Spain and Ireland by Popovici & Buhl (2010).

Biology

The genus Fidiobia contains more than a dozen species worldwide, of which seven are known from the Palaearctic. These wasps are endoparasitoids of beetle eggs, and consequently are very small, typically 0.6–1.3 mm, and rarely collected ( Popovici & Buhl 2010). Fidiobia hispanica was previously reared from the galls of Andricus lignicola by O’Connor et al. (2004), although the host remains were not located, and the host identity not confirmed. Spanish material was collected in a pine / juniper forest ( Popovici & Buhl 2010). In the present study two broods of F. hispanica were reared. The first was from a batch of beetle eggs found in a vacated gall of Andricus lignicola on Quercus robur . The host eggs were in a small irregular chamber at the base of the gall connected to the outside by a hole. There were at least 34 host eggs, 22 of which had been parasitised. (31 empty shells, 16 ♀♀, 3 ♂♂ emerged, 3 unemerged). The second brood was reared from a batch of beetle eggs found in a vacated Synergus umbraculus cell in an old vacated Andricus kollari gall. In both cases the galls were old, previously vacated and of weathered appearance, and in both cases the hosts were beetle eggs and not the original inhabitants of the gall. There have been several other rearings of other Fidiobia species from oak galls (e.g., Vlug 1995; O’Connor et al. 2004), which may be explained the same way – Fidiobia reared from oak galls are not using Cynipidae or their inquilines or parasitoids as hosts; it is much more likely that they are attacking beetle eggs which have been laid in cavities in old oak galls. Furthermore, the possibility should be kept in mind that F. hispanica has no particular association with oak galls. Probably there is a sampling bias since many people rear oak galls, and there is currently no reason to suppose F. hispanica would not attack the same beetle eggs elsewhere, such as in bark crevices.

Figures

Figs 1–3. Fidiobia hispanica Popovici & Buhl, 2010. 1. Dorsal habitus, ♀. 2. Host egg with half emerged ♀. 3. Fragment of old Andricus kollari gall showing cavity - a vacated cell of Synergus umbraculus – containing beetle eggs, the true host of F. hispanica. Body length of wasp c. 0.8 mm. © Ovidiu Popovici.