Leptocybe invasa

Kim, Il-Kwon, Mendel, Zvi, Protasov, Alexey, Blumberg, Daniel & Salle, John La, 2008, Taxonomy, biology, and efficacy of two Australian parasitoids of the eucalyptus gall wasp, Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae: Tetrastichinae), Zootaxa 1910, pp. 1-20 : 4-5

Taxonomy of Leptocybe invasa parasitoids

The two species described in this paper, Quadrastichus mendeli and Selitrichodes kryceri , are both in the Eulophidae subfamily Tetrastichinae . Australian Eulophidae were treated by Bouček (1988), who provided a key to all genera. Unfortunately, concurrent to Bouček’s studies, Graham was revising European Tetrastichinae , and provided a much revised classification of European genera ( Graham 1987), which appeared after Bouček’s work had already gone to press. For this reason, some genera treated by Bouček (1988) do not reflect current generic interpretations in the Tetrastichinae ( Graham 1987, 1991; La Salle 1994; Schauff et al. 1997). In particular, Bouček treated several genera as synonyms of Aprostocetus which need re-examination in light of these subsequent studies.

Terminology used in this paper is taken from Gibson (1997) and Graham (1987). OOL, ocellar–ocular distance; POL, post-ocellar distance; CC, costal cell; SMV, submarginal vein; MV, marginal vein; STV, stigmal vein; PMV, postmarginal vein; PDL, pedicel; F1–3, funicular segment 1–3; A1–3, anellus 1–3; C1–3, claval segment 1–3.

Acronyms used in the text are as follows. ANIC, Australian National Insect Collection, CSIRO Entomology, Canberra, Australia; BMNH, Natural History Museum, London, UK; QMB, Queensland Museum, Brisbane, Australia; USNM, United States National Museum of Natural History, Washington, D.C., USA.

Girault types and dates of publication. A.A. Girault published extensively on Australian Chalcidoidea, several thousand species. As part of this study, types of species of Tetrastichinae described by Girault and stated as being associated with galls were borrowed and studied, and several of his genera and species are discussed in this paper. Unfortunately, the identity of his type specimens is not always straightforward ( Dahms 1978). A series of works has discussed the identity of his Australian types and resolved most of the confusion regarding them ( Dahms 1983, 1984, 1986).

An additional challenge when studying Girault species is that in many cases the type material is in extremely poor condition ( Dahms 1978). Specimens are often fragmented and/or damaged, with parts missing or mounted on poor quality slides. This has prevented us from being able to fully understand and discuss all of the species in this paper, and makes some of the decisions tentative.

Due to the Principal of Priority (ICZN 1999), it is essential to know the exact dates of Girault’s publications (for example, Girault published 49 papers in 1913). Publication dates for all of his papers are listed by Dahms (1978), who also ordered all of Girault’s papers by date of publication. The numbers in brackets given in this paper refer to the numbering given in Dahms (1978).

Taxonomic decisions. All taxonomic decisions in this paper should be attributed to Kim & La Salle.

Differences between Quadrastichus mendeli and Selitrichodes kryceri

Although Q. mendeli and S. kryceri are placed in different genera, they are superficially very similar in appearance, being mainly yellow with black markings (see Figs 1–3 ), and they could easily be confused. The following characters are presented to facilitate their identification by non-specialists. Note that these characters are only to be used to distinguish the two parasitoids imported and released in the Mediterranean Basin.

Unfortunately, the morphological characters can still be difficult to see without microscopic examination. Other characters might be useful, but are not totally reliable. For example, S. kryceri generally has the gaster a dusky yellow, with 5–6 dark bands ( Fig. 2 ), while Q. mendeli has the gaster brighter yellow, usually with 3–4 dark bands ( Fig. 1 ). However, this character is variable, and in some specimens of S. kryceri the bands can be completely lacking ( Fig. 3 ). Similarly, in Q. mendeli the gaster generally appears longer and narrower than in S. kryceri (compare Figs 1 and 2 ); however there is overlap in this character and measurements cannot be provided which will reliably separate all specimens of these species.

Figures

FIGURES 1 – 3. Habitus. 1. Quadrastichus mendeli Ψ; 2. Selitrichodes kryceri “ dark ” specimen Ψ; 3. Selitrichodes kryceri “ light ” specimen Ψ