Bactrocera (Tetradacus) ernesti Leblanc & Doorenweerd

Leblanc, Luc, Doorenweerd, Camiel, Jose, Michael San, Pham, Hong Thai & Rubinoff, Daniel, 2018, Descriptions of four new species of Bactrocera and new country records highlight the high biodiversity of fruit flies in Vietnam (Diptera, Tephritidae, Dacinae), ZooKeys 797, pp. 87-115 : 93-95

Bactrocera (Tetradacus) ernesti Leblanc & Doorenweerd sp. n.

Holotype.

Male. Labelled: "Vietnam: Thừa Thiên-Hu ế Province, Bạch Mã National Park, 16.2297N, 107.8494E, 6-8-x-2015, M. San Jose and D. Rubinoff, FF485, zingerone lure. Molecular voucher ms6192". Deposited in UHIM. Paratypes: 5 males. Same data as holotype. All specimens pinned and one specimen is molecular voucher ms6255. Three of the paratypes are deposited at UHIM, one at WFBM and one at VNMN.

Differential diagnosis.

Bactrocera ernesti is similar to other members of the subgenus Tetradacus in having an elongate oval abdomen with a petiolate base [oval in most Bactrocera ] with separate terga [tightly joined in Dacus ], and a slight concavity of sternum V and short surstylus lobe in the males. It is most similar to B. minax and B. brachycera , but differs from both in lacking a lateral yellow band connecting the postpronotal lobes to the notopleural suture, the absence of medial postsutural vitta, the anteriorly convergent lateral postsutural vittae, the lightly infuscate wing, and absence of distinct costal band, and the black bands on every abdominal segment.

Molecular diagnostics.

B. ernesti sp. n. was referred to as Bactrocera species 73, represented by the holotype, in the seven-gene phylogeny presented in San Jose et al. (2018). Based on the sampling therein, its closest relative is B. (Tetradacus) tsuneonis (Miyake). The closest relative we could identify based on COI alone is the Australian species B. visenda , at a minimum intraspecific pairwise genetic distance of 13.52 % [14.89 % in COI5P and 12.27 % in COI3P] (Figure 3).

Description of adult.

Head (Figure 4A). Vertical length 1.82 ± 0.04 (SE) (1.75-1.85) mm. Frons, of even width, length 1.16 ± 0.05 (1.10-1.26) times breadth; uniformly fulvous; anteromedial hump and frons covered by short red–brown hairs; orbital and frontal setae, when present, red–brown: orbital setae absent or at most very weak and frontal setae very weak and may be restricted to superior pair; lunule fuscous. Ocellar triangle black. Vertex fulvous. Face fulvous with elongate black spot in lower half of each antennal furrow, connected by a faint narrow fuscous band across mid height of face; length 0.69 ± 0.02 (0.65-0.70) mm. Genae fulvous, with fuscous sub–ocular spot; one large and numerous smaller red–brown setae present. Occiput fulvous with fuscous markings laterally on its lower half; occipital row with 9-13 dark setae and an irregular inner row of finer setae. Antennae with segments 1 (scape) and 2 (pedicel) fulvous, segment 3 (first flagellomere) fulvous with pale fuscous on outer surface; a strong red–brown dorsal seta on segment 2; arista black (fulvous basally); length of segments: 0.19 ± 0.01 (0.18-0.20) mm; 0.26 ± 0.02 (0.23-0.28) mm; 0.76 ± 0.04 (0.70-0.83) mm.

Thorax (Figure 4B, E). Scutum red–brown except a broad light fuscous lanceolate pattern on its posterior third, anteriorly prolonged into three very narrow lines reaching anterior margin, narrow elongate dark fuscous bands adjacent to inner margins of lateral postsutural vittae, broad lateral dark fuscous markings behind postpronotal lobes and two short and narrow parallel dark fuscous bands between postpronotal lobes. Pleural areas dark fuscous except red–brown below postpronotal lobes, anterior half of anepisternum and posterior portion of katepisternum. Yellow markings as follows: postpronotal lobes; notopleura; medium sized and parallel-sided mesopleural (anepisternal) stripe, reaching anterior margin of notopleuron, continuing to katepisternum as a transverse spot, anterior margin straight; entire katatergite except red–brown narrowly along posterior margin; lower quarter to half of anatergite (remainder dark fuscous and red-brown on posterior margin of lower quarter to half); two moderately broad parallel sided lateral postsutural vittae ending shortly before intra-alar setae and curved slightly inwards along notopleural suture. Postnotum medially red–brown and laterally black. Scutellum yellow except for narrow dark fuscous basal band. Setae: 2 scutellar; 1 intra-alar; 1 posterior supra-alar; 1 mesopleural; 4 notopleural; 4 or 6 scapular (often a second pair of median scapular, just behind each bristle); anterior supra-alar and prescutellar bristles absent; all setae well developed and red–brown.

Legs (Figure 4E). Fore coxae yellow with outer face dark fuscous; fore trochanters and mid coxae and trochanters yellow; hind coxae and trochanters dark fuscous. Femora yellow with broadly fuscous outer and inner surfaces. Fore and mid tibiae fulvous with dark fuscous on outer face of fore tibia and around base of mid tibia; hind tibiae dark fuscous. Tarsi fulvous with dark fuscous fore tarsomeres 2-5 and ventral face of fore basitarsus. Mid-tibiae each with an apical black spur.

Wings (Figure 4D). Length 7.56 ± 0.21 (7.22-7.78) mm; basal costal (bc) cell infuscate and costal (c) cells mostly colorless except at apex; microtrichia along costal margin of cell bc and along costal margin and outer corner of cell c; remainder of wings colorless except fuscous subcostal cell, and lightly infuscate membrane between R1 and R4+5; supernumerary lobe weakly developed.

Abdomen (Fig. 4C, E). Elongate oval and petiolate; terga free; pecten present on tergum III; posterior lobe of surstylus short; abdominal sternum V with a slight concavity on posterior margin. Tergum I as long as wide and tergum II and sterna I and II longer than wide. Tergum I medially fuscous with a faint narrow fuscous medial longitudinal band and laterally black. Tergum II yellow with a large inverted V-shaped medial marking. Tergum III black with large apical triangular yellow marking. Tergum IV black with apical fulvous band with a medial expansion; tergum V fulvous with a narrow basal black band expanded laterally to half the tergum length. Abdominal sterna dark, except yellow sternum II.

Etymology.

This species is named after Ernest James Harris (1928-2018), in honor of his long career working as a fruit fly ecologist for the USDA (1962-2006). Some of Dr. Harris’s important contributions include the field implementation of the first eradication program against invasive fruit flies in the Mariana Islands, the establishment of Mediterranean fruit fly suppression programs in North Africa and Chile and studies on its ecology and SIT in Hawaii, as a prelude to the initiation of the ongoing SIT program to prevent its establishment in California, and the development of mass rearing techniques of the fruit fly parasitoid Fopius arisanus (Sonan). He published over 120 scientific papers and was honored with distinctions by the State of Arkansas Black Hall of Fame (1999), the NAACP Hawaii Chapter (2012), the Alpha Phi Alpha Fraternity National award (2013), the US Congressional Gold Medal (2016), the USDA-ARS Hall of Fame (2017), and as CTAHR Outstanding Alumnus (2017). His emergence as African American from a modest cotton farming family in Arkansas to an internationally respected prominent scientist, through hard work and his love for his research, makes Ernie a true role model for the senior author of this paper. Biographic sketches of Dr. Harris were published by Riddick et al. (2015) and Leblanc and Vargas (2018, in press).

Notes.

Bactrocera ernesti keys to couplet 2, page 314, in Drew and Romig (2016), where it can be differentiated from B. minax and B. brachycera based on the characters mentioned in the differential diagnosis.