Ooctonus Haliday, 1833

Triapitsyn, Serguei V., 2010, Revision of the Palaearctic species and review of the Oriental species of Ooctonus (Hymenoptera: Mymaridae), with notes on extralimital taxa 2381, Zootaxa 2381 (1), pp. 1-74 : 11-13

Ooctonus Haliday, 1833

Ooctonus Haliday 1833: 343 . Type species: O. insignis Haliday , by subsequent designation ( Westwood 1839: 78).

Ooctonus Haliday : Walker 1846: 49 (key), 50; Foerster 1847: 198–200 (review of species); Foerster 1856: 116 (key), 120 (comments); Dalla Torre 1898: 430–431 (catalog); Girault 1929: 20–22 (brief diagnosis and key to Nearctic species); Whittaker 1931: 192 (key to Nearctic species); Soyka 1941: 80–81 (taxonomic history); Debauche 1948: 114– 116 (redescription, diagnosis); Soyka 1949: 32–35 (taxonomic history, diagnosis, key to species), 79 (list of species outside of Europe); Kryger 1950: 76–79 (diagnosis); Hincks 1952: 153–154 (taxonomic history, diagnosis, key to “British” species); Ison 1958: 68 (brief diagnosis); Annecke & Doutt 1961: 15 (distribution, comments); Peck 1963: 18–19 (catalog of Nearctic species); Viggiani 1973: 273 (description of male genitalia); Hellén 1974: 6–7 (brief diagnosis, key); Trjapitzin 1978: 524 (key); Graham 1982: 225 (brief comments); Donev 1983: 31 (distribution); Schauff 1984: 37–38 (diagnosis); Viggiani 1988: 560, 562–563 (brief comments); Viggiani & Jesu 1988: 1023–1024 (Italian species); Noyes & Valentine 1989: 42 (diagnosis); Subba Rao 1989: 140 (key to Oriental species); Yoshimoto 1990: 35–36 (diagnosis, list of species in the New World); Huber 1997: 501–502, 508 (key); Beardsley & Huber 2000: 3 (key), 16; Triapitsyn & Huber 2000: 604–606 (key), 614 (comments).

Sphecomicrus Haliday : Walker 1846: 50. Type species: O. insignis Haliday , by subsequent designation ( Peck 1951: 410). Synonymized under Ooctonus by Kryger 1934: 504–505.

Diagnosis. Face without subantennal grooves ( Figs 24 , 33 , 58 , 117 ). Female antenna with funicle 8-segmented and clava entire, the latter usually with 7 mps, but sometimes with 8 mps; male antenna with flagellum 11-segmented. Pronotum entire, with usually a short, narrow collar. Prosternum divided mediolongitudinally ( Fig. 68 ). Mesoscutum and scutellum at least partially with reticulate sculpture. Propodeum with a diamond-like pattern of distinct carinae forming five areoles [normally a median pentagonal areole, formed by a transverse carina at posterior margin of the propodeum and two, angled, sublateral carinae that usually meet medially, often at some distance from posterior margin of the dorsellum (e.g., Figs 23 , 29 ); the areole is usually connected by a longitudinal median carina (of varying length depending on the species) that extends from its anterodorsal apex to the posterior margin of the dorsellum; the median areole is bordered on each side by a larger areole anterolaterally and a smaller areole posterolaterally; these, in turn, are bordered sublaterally by stronger, fairly straight lateral carinae extending from the carina surrounding the metacoxal foramen to or almost to the posterior margin of the dorsellum (e.g., Figs 10, 11)]. Forewing disc generally densely setose behind and beyond marginal vein; venation about one-third length of forewing (except in brachypterous females of O. hemipterus Haliday and two undescribed species from the Nearctic region); hypochaeta originating on membrane at anterior margin of forewing just above base of marginal vein, next to proximal macrochaeta. Tarsi 5-segmented. Petiole at least 1.8x as long as wide. In lateral view, first gastral tergum (= second metasomal tergum) usually at least as long as remaining gastral terga. Ovipositor usually at most a little exserted beyond apex of gaster but markedly exserted in two Nearctic species. Male genitalia with phallobase long, tubular.

Classification. Ooctonus is a relatively easily genus to recognize, so any generic key to the Mymaridae may be used to identify it: Annecke & Doutt (1961) for the world genera, Yoshimoto (1990) for the New World genera, Huber (1997) for the Nearctic genera, and Triapitsyn & Huber (2000) for the Palaearctic genera. It is most similar to Boudiennyia Girault , its sister genus from Australia, which has a different arrangement of carinae on the propodeum, with a distinct transverse carina joining the longitudinal submedian carinae ( Lin et al. 2007), and the venation about half-length of the forewing.

The place of Ooctonus within the higher hierarchy of Mymaridae and its relationships with other genera were discussed by Schauff (1984), who placed it in the cladogram (together with Gonatocerus ) next to the Alaptus group and other genera with 5-segmented tarsi. Viggiani (1989) placed Ooctonus in Ooctonini Ashmead ( Mymarinae ) based solely on the external male genitalic characters. Huber (2002) justifiably placed Ooctonus in the same clade with Boudiennyia . Lin et al. (2007) placed Ooctonus and Boudiennyia in the Ooctonus group of genera and indicated their likely relationship to the Polynema group of genera. I agree with their preliminary conclusions, although having supporting evidence based on molecular data would be helpful. Because the existing higher classifications of Mymaridae are not natural, the proper placement of Ooctonus within the family cannot yet be determined confidently.

Distribution. Nearctic, Neotropical (at high altitudes as far south as Costa Rica), Oriental, and Palaearctic regions, Hawaiian Islands ( Beardsley & Huber 2000), Papua New Guinea, and South Africa; one species ( O. vulgatus Haliday ) was apparently unintentionally introduced into New Zealand.

Host associations. Biology of members of Ooctonus is practically unknown except for the following, more or less reliable, host associations. Ooctonus orientalis Doutt was reared in Japan from eggs of the leafhoppers ( Hemiptera : Cicadellidae ) Cicadella viridis (Linnaeus) ( Doutt 1961) [as Tettigella viridis (Linnaeus) ] and Nephotettix cincticeps (Uhler) ( Sahad 1982) . Ooctonus notatus Walker was recorded [as O. heterotomus Foerster ] by Bakkendorf (1934) from eggs of an unknown “?hemipterous” insect in Denmark; Bakkendorf also studied the preimaginal development and other aspects of the biology of O. notatus . Bakkendorf (1934) also mentioned an Ooctonus sp. from Denmark as a possible egg parasitoid of Aphrodes sp. [as Acocephalus sp. ] ( Cicadellidae ). In the USA, several species of Ooctonus were reared from eggs of Aphrophoridae (Hemiptera) [sometimes included in Cercopidae ]: O. aphrophorae Milliron from Aphrophora saratogensis (Fitch) ( Milliron 1947) , and O. vulgatus Haliday [as O. americanus Girault ], as well as O. sp. and O. “n. sp.” from Philaenus spumarius (Linnaeus) ( Weaver & King 1954) [as P. leucophthalmus (Linnaeus) ]. The reported possible associations of the Nearctic species O. quadricarinatus Girault with Pityogenes hopkinsi Swaine ( Coleoptera : Curculionidae ) ( Girault 1916b), and also of the Holarctic species O. vulgatus with Sciara analis Schiner ( Diptera : Sciaridae ) ( Pricop 2009a; but see comments by Viggiani & Jesu 1988) need verification – most likely they are erroneous.

Remarks. The Australian species that had been described originally in Ooctonus were transferred to Gonatocerus by Lin et al. (2007). From the original description and illustrations of Ooctonus sevae Risbec from Madagascar ( Risbec 1955), it is clear that this species also belongs in Gonatocerus , apparently in the subgenus G. (Lymaenon Walker) as defined by Triapitsyn et al. (2010). This is based on examination of the following specimens from Madagascar which seem to be conspecific with this very distinctive, peculiar Risbec’s species: FIANARANTSOA, Ranomafana, JIRAMA water works, 21°14.91’S 47°27.13’ E, 690 m, 16.x– 8.xi.2001, R. Harin’Hala, MT (MA-02-09D-01) [1 ♀, CAS]; TOLIARA, Fôret Classée d’Analavelona, 29.2 km 343° NNW of Mahaboboka, 22°40°30’’S 44°11’24’’ E, 1100 m, 18–22.ii.2003, B. Fisher, T. Griswold, YPT in montagne rainforest (BLF7822) [1 ♀, 1 ♂, CAS]. Consequently, O. sevae is transferred here to Gonatocerus as G. (Lymaenon) sevae (Risbec) , comb. n. This species, which has F5 and F6 of the female antenna white ( Fig. 7 ), a very long petiole and the forewing disc bare behind the entire venation, is very unusual for G. (Lymaenon), where it is tentatively placed based mainly on the structure of its mesosoma ( Fig. 8 ): the dorsellum is strap-like, and the lateral lobes of the pronotum are separated by apparently a lightly sclerotized, although unusually very narrow, median area (so that without a closer look, the pronotum superficially seems to be 2-lobed). Its habitus is thus superficially very similar to that of some New World species from the morrilli subgroup of the ater species group of G. ( Cosmocomoidea Howard ), as defined by Triapitsyn et al. (2010), such as some members of G. (Cosmocomoidea) morrilli (Howard) complex, which also have a mostly light brown body, F5 and F6 of the female antenna white, a long petiole, and no or very few setae behind the marginal and stigmal veins on the forewing disc.

Figures

FIGURES 21–26. Ooctonus insignis ♀ (Ham, Surrey, England): 21, antenna; 22, mesosoma; 23, posterior scutellum, metanotum, and propodeum; 24, head (frontal view); 25, forewing; 26, hind wing.

FIGURES 32–37. Ooctonus lokomotiv ♀ (holotype): 32, antenna; 33, head (frontal view); 34, mesosoma; 35, posterior scutellum, metanotum, and propodeum; 36, gaster; 37, wings.

FIGURES 57–60. Ooctonus orientalis ♀ (Gornotayozhnoye, Primorskiy kray, Russia): 57, antenna; 58, head (frontal view); 59, propodeum; 60, forewing.

FIGURES 116–120. Ooctonus himalayus ♀ (Phulcoki, Lalitpur, Bagmati, Nepal): 116, antenna; 117, head (frontal view); 118, mesosoma; 119, propodeum; 120, wings.

FIGURES 65–71. Ooctonus saturn ♀ (paratypes, Gornotayozhnoye, Primorskiy kray, Russia): 65, antenna; 66, mesosoma; 67, posterior scutellum, metanotum, and propodeum; 68, prosternum and propleura; 69, gaster; 70, forewing; 71, hind wing.

FIGURES 28–31. Ooctonus insignis ♂ (Abergele Coed y Gopa, Denbigh, Wales): 28, antenna; 29, mesosoma; 30, genitalia; 31, forewing.

FIGURES 7, 8. Gonatocerus (Lymaenon) sevae ♀ (21°14.91’S 47°27.13’E, Ranomafana, Fianarantsoa, Madagascar): 7, antenna; 8, mesosoma.