Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault, 1979)

Vogel, Jonathan, Martin, Jakob, Forshage, Mattias, Salden, Tobias, Staverløkk, Arnstein, Verheyde, Fons, Nordlander, Göran, Herz, Annette & Peters, Ralph S., 2025, The Leptopilina Förster, 1869 of the Western Palearctic, and an updated list of the world species (Hymenoptera, Figitidae, Eucoilinae), Journal of Hymenoptera Research 98, pp. 915-969 : 915-969

Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault, 1979)

Charips mahensis Kieffer, 1911: 312 – secondary junior homonym in Leptopilina of Erisphagia mahensis Kieffer, 1911 .

Cothonaspis ( Cothonaspis) boulardi Barbotin, Carton & Kelner-Pillault, 1979: 20–26 .

Diagnosis.

Leptopilina boulardi is a small to medium-sized species (up to 1.5 mm ♀ body length) with a stout appearance and relatively short appendages (Fig. 3 A ).

The species is unique by its smooth metapleuron, having at most a short ridge 2 and the other ridges absent (Fig. 3 D ). In all other species, the three ridges are at least somewhat developed. Also, the propodeal carinae are diverging to a varying degree in the posterior half of the propodeum (Fig. 3 E ). Other species have their propodeal carinae running uniformly straight or outwardly curved from the anterior to the posterior margin of the propodeum.

The sculpture on the dorsal surface of the mesoscutellum is striate. The striae are radiating from the base of the mesoscutellar plate (Fig. 3 C ) and the posterior surface is areolate. The sculpture of L. heterotoma is similar, though the striae are more dispersed elong the entire length of the mesoscutellar plate and the posterior surface is foveate-reticulate. In other species, the mesoscutellum is sculptured entirely foveate-reticulate. Just as in L. japonica , the setal patch on the base of the metacoxa of L. boulardi is absent. There are at most a few singular setae (Fig. 3 D ).

The forewing is usually relatively small with a narrow, elongate marginal cell, but can be different and is thereby not sufficient as a diagnostic character.

Biology.

Habitat. Occurs in forests and orchards.

Flight period. At least June to October, mainly July to August, in European data. Clearly able to breed around the year in warm climates, as it is present also in winter months in Macaronesia and North Africa. In data from the USA, there seems to be a distinct spring generation in May, also, there is a record from January in Florida.

Hosts. Specialist of fruit-inhabiting Drosophila ; emerged from D. melanogaster and D. simulans Sturtevant, 1919 in fermenting fruits ( Nordlander 1980; Vet and van Alphen 1985; van Alphen and Vet 1986; Fleury et al. 2009). Attacks D. suzukii , but is not able to develop in this host ( Chabert et al. 2012) and is not suitable for application in biological control ( Gonzalez-Cabrera et al. 2019).

Ex situ: Reared from D. virilis Sturtevant, 1916 and the non-Western Palearctic species D. erecta Tsacas & Lachaise, 1974 , D. eugracilis Bock & Wheeler, 1972 , D. mauritiana Tsacas & David, 1974 , D. pseudoobscura Frolova & Astaurov, 1929 , D. sechellia Tsacas & Bächli, 1981 , D. teissieri Tsacas, 1971 ; in some cases, with very high encapsulation rates ( Schlenke et al. 2007).

Population parameters. Relative abundance in summer is parallel to D. simulans ( Fleury et al. 2004; Mazzetto et al. 2016). French populations of L. boulardi were fully pro-ovigenic and developed at temperatures between 20–28 ° C ex situ ( Moiroux et al. 2013). Thermal reaction and life history parameters are adapted to macrohabitat and less to geographic range, indicating an adaption to the habitat-specific host range ( Moiroux et al. 2013). No Wolbachia Hertig, 1936 symbionts were detected in examined populations ( Vavre et al. 2009; Wachi et al. 2015).

Distribution.

Cosmopolitan species; in Western Palearctic with a center in the Mediterranean region and not extending far north: found in the Canary Islands, France, Greece, Iran, Italy, Madeira, Portugal, Serbia, Spain, Switzerland, Tunisia and Turkey. Also present in the Afrotropics: Democratic Republic of the Congo, Republic of the Congo, Gambia, Ivory Coast, Kenya, Madagascar, Seychelles (locus typicus of Charips mahensis ), South Africa, Zambia and Zimbabwe; in North America: Canada and USA (east and west); South America: Argentina, Brazil, Guadeloupe (locus typicus of Cothonaspis boulardi ), and Mexico; and in Australia and Vanuatu. We have not seen records from tropical Asia, but the species is probably also present there.

Remarks.

Originally described as Charips mahensis Kieffer, 1911 , the name became a secondary homonym with Erisphagia mahensis Kieffer, 1911 when both species were moved into Leptopilina by Nordlander (1980). The junior synonym name Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault, 1979) was available and became the valid name of this species, whereas it is the other species, originally Erisphagia mahensis Kieffer, 1911 which is now Leptopilina mahensis (Kieffer, 1911) .

The species was diagnosed and redescribed in Lue et al. (2016) and Nordlander (1980) describes and illustrates some of the morphological variation regarding the propodeal carinae in different L. boulardi strains.

We obtained specimens from a laboratory population late during the project and did not see the necessity to sequence the species ourselves because many records identified as L. boulardi by hymenopterist experts are already available in GenBank, BOLD and DROP and represent a singular BIN ( BOLD: ACB 7933, note that one likely erroneously associated specimen image does not show a Leptopilina boulardi but an aculeate wasp, accessed 27 th June 2025). An unambigous identification of the species with CO 1 barcode data or morphology is comparably unproblematic. We neither included sequences from external sources into the dataset for the species delimitation, nor utilised them for the molecular characterisation of L. boulardi because we only included those sequences in the analyses which we could examine morphologically ourselves.

Figures

Figure 3. Female specimen of L. boulardi (ZFMK - HYM- 00039733) A lateral habitus B left antenna C dorsal view on mesoscutellum D lateral view on metapleuron and base of metacoxa E posterior view on mesoscutellum and propodeum.