Tamarixia dahlsteni Zuparko

Zuparko, Robert L., Queiroz, Dalva Luiz De & Salle, John La, 2011, Two new species of Ta m a r i x i a (Hymenoptera: Eulophidae) from Chile and Australia, established as biological control agents of invasive psyllids (Hemiptera: Calophyidae, Triozidae) in California, Zootaxa 2921, pp. 13-27 : 21-24

Tamarixia dahlsteni Zuparko , sp. nov.

( Figs 9–16 )

Diagnosis. Female T. dahlsteni are easily distinguished from all other described Tamarixia species from North America by an extensively yellow gaster (rather than completely dark). The entire ventral surface of the gaster is yellow, and dorsally the yellow extends to or slightly beyond the apex of the 2nd gastral tergite ( Fig. 9 ). There is an undescribed species of Tamarixia from Florida (ex. Ceropsylla sideroxylii on Sideroxylon foetidissimum Jacquin , EMEC, ANIC) that also has yellow markings on the gaster, but in that species the dorsal yellow coloration extends to the apex of the gaster, although it may be interrupted by one or more transverse brown stripes. Additionally, T. dahlsteni has a distinct paraspiracular carina medial to the propodeal spiracle that is posteriorly bifurcate ( Figs 15, 16 ), similar to that seen in species of Tetrastichus . This is the only species of Tamarixia in North America with such a carina. Males of T. dahlsteni are less distinctive, but are separable from those of other Tamarixia species by a combination of a posteriorly bifurcate paraspiracular carina, forewing with a wide speculum, 3rd and 4th funicle segments 2.0x or longer than wide, and fore femur distinctly lighter than the hind femur.

Description. FEMALE. Body length: 0.87–1.25 mm; wingspan: 2.44–3.24 mm. Shiny black; eye dark red, ocelli bright red; scape yellow-brown, pedicel and flagellar segments light brown, darkened at base of each segment, markedly more so dorsally, club light brown; legs yellow, hind legs sometimes slightly darker, fore and hind coxae concolorous with body, the latter yellow apically, ultimate tarsal segment darkened apically; gaster with basal yellow spot extending about 0.5x length dorsally and entire length ventrally. Wing hyaline, veins brown. Relative measurements: head (slightly collapsed) width: 32, length: 12, height: 24; width of frons: 17, OOL: 4, POL: 9; eye length: 12, width: 14; malar space: 7; antennal segments (length:width): scape, including radicle: (13:3), pedicel: (5:2.5), F1: (5:3), F2: (5:2.5), F3: (5:2.5), club, including spicule: (11:3.5); mesosoma length: 34, width at tegulae: 28, height: 25; width of scutellar median area: 5, sublateral areas: 5; gaster length: 26, width: 23.5; fore wing length: 80, width: 37; length costal cell: 20, marginal vein: 17, stigmal vein: 7; hind wing length: 62, width: 11. Antenna inserted slightly above lower level of eye, scape reaching anterior ocellus. Eye with short hairs. Mesoscutum with median line complete, but less distinct anteriorly, and 2 or 3 pairs of adnotaular setae. Head and mesosoma reticulate, except propodeum more rugose. Propodeum with distinct median carina, callus moderately developed with 2 setae, spiracle elongated, almost touching anterior edge of propodeum. Ratio of median lengths of dorsellum:propodeum = 3:4. In profile, posterior portion of scutellum, dorsellum and propodeum in the same plane, inclined about 50o from longitudinal axis of the body. Fore wing apically rounded, almost truncate; stigmal vein basally appearing markedly constricted, expanding apically and uncus present but less protuberant than in T. schina ; postmarginal vein absent; speculum extending from point posterior to parastigma diagonally apically and anteriorly to marginal vein, narrow hairless band posterior to marginal vein and basal portion of stigmal vein. Hind wing apically acute, vein extending to hamuli, about 0.5x wing length; longest length of fringe about 0.5x wing width.

MALE. Body length: 0.70–1.20 mm; wing span: 1.80–2.94 mm. As female, except antenna brown with darker dorsal infuscations on scape and pedicel, and occasionally on F2–F4, F1–C1 with long setae (2– 5 x segment length) attached basally; hind femur always darkened, occasionally also fore and mid-femora, and mid- and hind tibiae; gaster concolorous with mesosoma. Relative measurements of antennal segments (length:width): scape, including radicle: (11:3), pedicel: (4:2.5), F1: (4:4), F2: (6:3), F3: (7:3), F4: (8:3), C1: (5:2), C2: (4:2), C3: (4:2). Segments F1 to C1 basally with long setae, about 2–10x widest width of segment. Apex of forewing slightly less truncate than female. Speculum about same size as in female. Gaster length: 30, width: 17.. Genitalia with digitus long and narrow, length about 6– 7 x width, tipped with a hook curving laterad; paramere with an apical stylus and slightly shorter than digitus; aedeagus length 11x basal width, about 3x length of digitus, with apex acute.

Distribution. Australia (New South Wales), USA (coastal area of California).

Hosts. Known only from Trioza eugeniae , a primary ectoparasitoid of nymphs.

Type material. Holotype Ƥ: AUSTRALIA. NEW SOUTH WALES: 10 km W of Sydney, Ryde School of Horticulture, 20 Nov 1991, D. L. Dahlsten, Trioza eugeniae on Syzygium paniculatum, Quarantine #91- 16.1( ANIC). Paratypes: AUSTRALIA: Same data as holotype, 25 Ƥ, 13 3 ( ANIC, BMNH, CAS, USNM, QM, UCD, EMEC, UCR); Ryde, 22 Oct 1994, nymphs of Trioza eugeniae , 9 Ƥ, 7 3 ( ANIC); QUEENSLAND: Atherton, 2 Aug 1994, Bred from nymph of Trioza eugeniae , 1 Ƥ, 7 3 ( ANIC); WESTERN AUSTRALIA: Denmark, corner of Hollings Rd and Hwy 1 (South Coast Hwy), 3-6 Oct 2010, D.L. Queiroz & J. La Salle, from Trioza eugeniae on Syzygium paniculatum , S34° 57.588 E 117°21.385, 23 Ƥ, 19 3 ( ANIC). USA. CALIFORNIA. Alameda Co.: Albany, UC Gill Tract, 12 Aug 1994, R.L. Zuparko, swept from S. paniculatum , 5 Ƥ ( EMEC); Oakland, 6 Feb 1993, R.L. Zuparko, swept from S. paniculatum , 6 Ƥ, 1 3 ( EMEC); same location, 15–21 Aug 1993, T. Young, T. eugeniae on S. paniculatum , 3 Ƥ, 4 3 ( EMEC, UCD). Solano Co.: Vallejo, 1 Jun 1994, R.L. Zuparko, swept from Tilia cordata Miller (Tiliaceae) , 2 Ƥ ( EMEC).

Etymology. The species is named in honor of the late Dr. Donald L. Dahlsten (University of California, Berkeley), who directed the biological control program against T. eugeniae and conducted the foreign exploration which resulted in the discovery and importation of the species.

Discussion. Girault (1915) described Selitrichodella meteora and S. cometes from Australia. Bouček (1988a) thought both species might belong to Tamarixia and reported them as new combinations, noting that the information from the types was not conclusive. The two species are known only from female holotypes that are in poor condition, and in the case of T. cometes only by a broken head on a slide. Examination of the types (by RLZ) of the two Girault species (QM) was insufficient to confirm whether either belongs to Tamarixia , however, neither is conspecific with T. dahlsteni . The antenna of T. cometes is entirely yellow, except for a dark spot on the middle of the dorsum of the scape, and another on the dorsum of F1, whereas in T. dahlsteni the scape is yellow-brown without darkened areas, and the pedicel and flagellar segments are narrowly darkened basally. In T. meteora , the antenna is all yellow and almost the whole dorsum of the gaster is lightened, whereas in T. dahlsteni the gaster is lightened only basally.

According to Graham (1991), one of the three apomorphic characteristics of Tamarixia is the presence of two pairs of adnotaular setae of the mesoscutum. However, about one quarter of the T. dahlsteni specimens examined had 3 setae along either one or both notauli, indicating this is not a reliable character for determining the genus.

Tamarixia dahlsteni has been reported to be the most important natural enemy of T. eugeniae in southeast Australia, with the percentage parasitism ranging from 3–62% ( Young 2003).

Figures

FIGURES 9 – 12. Tamarixia dahlsteni. 9. Habitus, female. 10. Forewing, female. 11. Antenna, female. 12. Head and antennae, male.

FIGURES 13 – 16. Tamarixia dahlsteni, female. 13. Head, frontal view. 14. Mesosoma, lateral view. 15. Mesosoma, dorsal view. 16. Propodeum.