Gonatocerus ashmeadi Girault, 1915

Triapitsyn, Serguei V., 2006, A key to the Mymaridae (Hymenoptera) egg parasitoids of proconiine sharpshooters (Hemiptera: Cicadellidae) in the Nearctic region, with description of two new species of Gonatocerus, Zootaxa 1203, pp. 1-38 : 24-27

Gonatocerus ashmeadi Girault, 1915

( Figs 21–25 )

Gonatocerus dolichocerus var. ashmeadi Girault 1915: 8 .

Gonatocerus ashmeadi Girault : Girault 1929: 25; Huber 1988: 53 –55 (subsequent references, lectotype designation, redescription, diagnosis, distribution, host associations); Triapitsyn and Phillips 1996: 10; Triapitsyn et al. 1998: 241–242 (distribution, host associations); Triapitsyn, Bezark and Morgan 2002: 38 –39 (distribution, host associations); Vickerman et al. 2004: 338 –344 (biological, morphological, and molecular distinction between populations; distribution); de León 2004a: 314 –317 (molecular distinction between populations); Hoddle and Triapitsyn 2004b: 342 –343 (distribution, host associations); de León and Jones 2005: 1–7 (molecular distinction between populations); Triapitsyn et al. 2006: 60–62 (illustrations, comparison with G. u a t S. Triapitsyn).

Type locality

An unspecified locality in Texas, USA.

Material examined

EASTER ISLAND ( CHILE). Rano­Kau, 1.iii.2006, M. Beeche C. (ex. eggs of H. coagulata ) [3 females, 1 male, UCRC]. HAWAIIAN ISLANDS ( USA, HAWAII). Oahu Island, Keehi Lagoon, 3.xii.2004, R. Bautista (ex. eggs of H. coagulata on African tulip) [1 female, 3 males, CNCI]. MEXICO. TAMAULIPAS, Universidad Autónoma de Tamaulipas campus, 25.iii.2005 (emerged 1.iv. 2005 in UCR quarantine), S.V. Triapitsyn (ex. egg mass of Oncometopia sp. on hibiscus leaf) [1 female, UCRC]. USA. CALIFORNIA: Riverside Co., Riverside, UCR campus, 23.vii.1996, M. Grebus (ex. Homalodisca sp. eggs) [5 females, 5 males, UCRC]. Ventura Co., Fillmore: 12.vii.2000, R. Fenton (ex. H. coagulata eggs on lemon leaves) [11 females, 4 males, UCRC]; 23.viii.2000, R. Fenton (ex. H. coagulata eggs on lemon) [1 female, 1 male, UCRC]; 23.viii.2000, R. Fenton (ex. H. coagulata eggs on Valencia orange) [6 females, 4 males, UCRC]. FLORIDA: Jefferson Co., Monticello, 25.vii.2000, S.V. Triapitsyn (emerged in UCR quarantine 2–4.viii.2000 from an egg mass of H. coagulata ; adult glassy­winged sharpshooters sleeved on crape myrtle 18.vii.2000 by R. López, then sleeve removed and host eggs exposed 21.vii.2000) [7 females, UCRC]. GEORGIA: Houston Co., near Centerville, 32°38’03.3’’N, 83°43’06.4’’W, 131 m, 21.vi.2004 (emerged 22–30.vi. 2004 in UCR quarantine), S.V. Triapitsyn, T. Cottrell (ex. proconiine sharpshooter egg masses on grasses) [numerous females and males, UCRC]. Peach Co., Byron, 21–22.vi.2004, S.V. Triapitsyn (emerged 24.vi–6.vii.2004 at UCR quarantine from eggs of H. coagulata and O. orbona on leaves of crape myrtle, magnolia, etc.) [numerous females and males, UCRC]. NORTH CAROLINA, Carteret Co., Morehead City, 20–27.viii.2000, M. Wuenschel [3 females, UCRC]. SOUTH CAROLINA, Charleston Co., Charleston, 22–23.vi.2004 (emerged 25–29.vi. 2004 in UCR quarantine), S.V. Triapitsyn (ex. H. coagulata eggs on crape myrtle) [numerous females and males, UCRC].

Diagnosis

The main distinguishing features of this species are as follows (mostly after Huber 1988). Body length (female) 1280–1760. Head and mesosoma generally dark brown, legs and gaster mostly yellow with brown bands on gastral terga; gaster may be almost completely dark brown in some males. Longitudinal sensilla present on F2–F8 of the female antenna; F1 without sensilla ( Fig. 21 ). Mesosomal sternum with a distinct, welldefined yellow streak between each fore and middle coxae ( Fig. 22 ). Submedial carinae on the propodeum thick, distinct, reaching the dorsellum ( Fig. 23 ). Forewing ( Fig. 24 ) hyaline or at most with a faint uniform brown tinge; cubital row of microtrichia on forewing blade complete, extending to base of marginal vein. Habitus of the female is shown in Fig. 25 . Gonatocerus ashmeadi is most closely related to G. uat S. Triapitsyn (Triapitsyn et al. 2006) , from which it can be distinguished using the characters indicated in the key. Among the unrelated North American species of Gonatocerus , G. ashmeadi can be quite easily confused with another common and superficially very similarly looking (especially the coloration) species, G. dolichocerus Ashmead , which belongs to the bucculentus subgroup of the ater species group ( Huber 1988). Besides the subspecies­group distinguishing features indicated in Huber’s (1988) key to the North American species of the ater species group of Gonatocerus , females of G. dolichocerus can be separated from those of G. ashmeadi by a relatively shorter F 1. I myself accidentally misidentified several specimens of G. dolichocerus as G. ashmeadi ( Vickerman et al. 2004) , with the following label data: USA: Louisiana, East Baton Rouge Parish, Baton Rouge, 2–4.iv.2002, S.V. Triapitsyn [3 females, UCRC]; Missouri, St. Clair Co., Chapel View Prairie, 29.vi.1999, M.W. Gates [1 female, UCRC].

Distribution

Mexico (Nuevo León and Tamaulipas) and USA (California, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Texas); its occurrence in Alabama and southern Arkansas, although not documented, is also very likely. The southern and southeastern USA strains of G. ashmeadi were released in California against H. coagulata (Morgan et al. 2002; Pilkington et al. 2005). Self­introduced into Oahu Island, Hawaii ( USA), where G. ashmeadi provides a good control of H. coagulata ; intentionally and successfully introduced into Tahiti, Society Islands, French Polynesia, for biological control against H. coagulata (Mark S. Hoddle, personal communication). Self­introduced into Easter Island ( Chile) (new record), probably from French Polynesia; specimens were sent to me for identification by Sandra Ide Mayorga (Santiago, Chile). Triapitsyn et al. (2006) provided label data for the specimens of G. ashmeadi from Honolulu, Oahu Island, Hawaii ( USA) that were sequenced for the molecular comparison with the North American specimens of this species and also with G. u a t S. Triapitsyn.

Hosts

Cuerna costalis (Fabricius) , Homalodisca coagulata (Say) , H. liturata Ball , Oncometopia clarior (Walker) , O. orbona (Fabricius) , and Oncometopia sp. Biological traits of G. ashmeadi are well known (Irvin and Hoddle 2004; 2005a, b; Velema et al. 2005).

Comments

It can be supposed that G. ashmeadi might not be native to California; rather, it probably had accidentally introduced itself into California from somewhere in southern or southeastern USA long ago (before the 1980s) and established there on eggs of H. liturata , the local proconiine sharpshooter. Following establishment of H. coagulata in southern and central California during the 1990s, G. ashmeadi simply switched back to its natural host, providing good control of the summer brood of the glassy­winged sharpshooter. The molecular data reported by Vickerman et al. (2004) and de León and Jones (2005) may support such an assumption.

Figures

FIGURE 25. Gonatocerus ashmeadi (female). Photo by Jack Kelly Clark, University of California.

FIGURES 21 – 24. Gonatocerus ashmeadi (female). 21. Pedicel and basal funicle segments. 22. Mesosomal sternum. 23. Propodeum. 24. Forewing.