Tetrastichus giffardianus Silvestri, 1915

Shimbori, Eduardo Mitio, Costa, Valmir Antonio & Zucchi, Roberto Antonio, 2020, Annotated checklist and illustrated key to parasitoids (Hymenoptera: Diapriidae Eulophidae and Pteromalidae) of fruit flies (Diptera, Tephritidae) in Brazil, Zootaxa 4858 (1), pp. 53-70 : 60-61

Tetrastichus giffardianus Silvestri, 1915

( Figs 4, 5 )

Diagnosis. Color varying from dark-brown to black, with metallic bluish-green iridescence, more intense on the mesosoma; legs brown with pale-yellow tarsi. The species belongs to the murcia group ( Graham 1991), which includes five Old World species, distinguished mainly by the presence of long erect setae on the eyes, vertex and thorax. Within the murcia group, Te. giffardianus is distinct from other species in having a long speculum (area without setae) along the anterior margin of the fore wing, from its base to the stigmal vein or beyond ( Graham 1991; LaSalle & Wharton 2002).

Taxonomy. The species concept and its identification are relatively straightforward, thanks to the taxonomic revision of African species of Tetrastichus ( LaSalle & Wharton 2002) , which includes a key to species. Nevertheless, this revision is limited to three species from Africa, and the more comprehensive revision of Graham (1991) is helpful in the identification and confirmation of the taxonomic concept at the species-group level.

Biology. This is a gregarious, larval-pupal, koinobiont endoparasitoid ( LaSalle & Wharton 2002). Females search for hosts by penetrating fruits to oviposit in late-instar larvae of tephritid species ( Pemberton & Willard 1918; Fernandes et al. 2019). Adults will emerge from the puparium of their host, although oviposition occurs in the larva, a unique parasitism strategy among the species treated here, and closer to the biology of most the common species of Braconidae and Figitidae that parasitize fruit flies. All of the several species recorded as hosts of Te. giffardianus are tephritids, and most of them in the genus Ceratitis in its native distribution area. In Brazil, Te. giffardianus was reared from A. obliqua ( Araújo et al. 2016) and A. distincta ( Abreu et al. 2019) , however, a clear preference for Ce. capitata has been observed ( Costa et al. 2005; Araujo et al. 2015) ( Table 1 ).

Biological control. This species possesses the same biological traits, except for being gregarious rather than solitary, found in the main natural enemies of fruit flies ( Braconidae , Opiinae ), making them excellent candidates for biological control programs, especially for Ce. capitata . After confirmation that Te. giffardianus had established in Brazil, most successfully in the Northeast region, research on this parasitoid flourished. Currently, the efforts to mass-rearing this parasitoid, which started more than 70 years ago ( Fonseca 1947), are being renewed ( Fernandes et al. 2019).

Distribution. Widely distributed in Africa ( LaSalle & Wharton 2002). Introduced into several countries in the New World ( Argentina, Brazil, Colombia and Uruguay), and established in Brazil ( Costa et al. 2005) and Hawaii.

Distribution in Brazil. BA, CE, RN ( Costa et al. 2005), CE ( Araujo et al. 2015; Fernandes et al. 2020, MG ( Abreu et al. 2019), PI ( Araújo et al. 2016; Coelho et al. 2020), RN ( Fernandes et al. 2019), SP ( Montes et al. 2011).

Figures

FIGURES 1–8. 1, 2, Trichopria sp. aff. anastrephae, head; 3, Spalangia simplex, head; 4, 5, Tetrastichus giffardianus: 4, mesosoma dorsal and 5, fore wing; 6–8, Pachycrepoideus vindemmiae: 6, head, 7, mesosoma dorsal and 8, fore wing. Arrows indicating: point of insertion of the antenna (Figs 1–3, 6); submedian grooves on scutellum (Fig. 4); thickened marginal vein (Fig. 8). (bar = 0.1 mm)