Bactrocera

Description

 

Body. Slender, elongate, tapering anteriorly. Integument unsclerotized (occasionally with small patch of pigmented sclerotization ventrally on T1 or forming a transverse line below posterior spiracles), entirely whitish to yellowish. Caudal ridge present. Mature larvae able to jump. 

Head. Head of normal shape; cephalic lobes well-developed and prominently protruding, (occasionally slightly to moderately developed). 

Antenna 2-segmented. 

Stomal organ: a small, roundish primary lobe bearing a pit with 2–6 short to long peg-sensilla, sensilla branched or unbranched; primary lobe encircled by 3 or more petal-like secondary lobes at lateral end of a series of 2–3 additional, elongate petal- or leaf-like secondary lobes medially; margins of secondary lobes entire to serrate. 

Sclerotized stomal guards absent. 

Median oral lobe pointed, protruding between mouthhooks in line with secondary stomal lobes [ditto Ceratitis; vs Anastrepha with projection below level of stomal lobes]. 

Oral ridges present, margins variously serrate, scalloped or dentate (not entire). 

Accessory plates present, variable in size, shape, number, and serration. [exception: B. oleae]

Elongate, finger-like lobes arising above mandibles absent. 

Labium triangular with broad base.

 

Cephalopharyngeal skeleton. 

Mandibles: 

Mouthhooks ventrally grooved 

Mouthhook ventral surface smooth, with slight transverse ridges [

subapical teeth absent.  [exception non-pests: B. (B) manskii; B. (H) algaiae] ; 

base elongate, forming a more oblique angle [i.e., with a neck sensu Frias; vs perpendicular in Anastrepha] [exception: base stout in B. oleae]

Parastomal bars elongate, free from hypopharyngeal sclerite. [based on all drawings in W&EH]

Dental sclerites present, posterior to mandibles  [present in all EH drawings]

 

Anterior spiracles.

Anterior spiracle convex to flat or concave medially, appearing bilobed. 

Anterior spiracular tubules 7–21.

In a single uniform or irregular row. [all (?)’s in LEC except B. tsuneonis; ...review all EH and other images]

 

Spinules and creeping welts. Dorsal spinules on few to all segments; always T1-T2, sometimes extending as far as A2. Creeping welts present.

 

Caudal segment (A8) and anal lobes. Sensilla on caudal segment 10 pairs, with at least 7 pairs visible under dissecting microscope. Dorsal caudal sensilla obvious, sessile or on separate papillae or tubercles. Intermediate caudal sensillum I3 obvious, but not on a papilla or tubercle. Lateral caudal sensillum obvious, but not on a papilla or tubercle. Intermediate caudal sensilla I1a and Ib obvious, on a single papilla or tubercle, bifid apically. Intermediate caudal sensillum I2 obvious. Intermediate caudal sensilla I1a and Ib and I2 on separate papillae or tubercles. Ventral caudal sensilla absent or visible only with great difficulty, or obvious, but not on a papilla or tubercle (2 pits, 1 papilla). [exception: Unusual arrangement in B. tsuneonis].

Anal lobes plainly visible, occasionally protuberant; simple, grooved, or bifid. 

Posterior spiracles. Posterior spiracular area not distinctly set off from caudal segment. Three posterior spiracular openings arranged approximately in parallel, each with well-sclerotized rima and inner trabeculae, 2.5-5 times longer than wide. Four sets of spiracular processes (dorsal, intermediate 1 and 2, and ventral) comprising a variable number of bristles (counted as trunks) in a linear series arising from a short to long, curved to semicircular base, unbranched to multiply branched (counted as tips). Area between posterior spiracles smooth [exception: with vertical wrinkles in B. bryoniae]. 

Host plants

Many families. Many species are highly polyphagous, with some having over 250 known host plant species (Vargas et al. 2015)

Part of plant attacked: fruit or seed. 

Biogeographic region and distribution

Excerpt from Vargas et al. (2015):

The genus Bactrocera is widely distributed throughout tropical Asia, the south Pacific and Australia. Relatively few species exist in Africa, and only the olive fly, B. oleae (Rossi), occurs in Southern Europe. Recently, B. oleae became established in California, and two species in the B. dorsalis complex became established on two new continents: B. carambolae Drew & Hancock, the carambola fruit fly, in South America (Suriname) and B. dorsalis (formerly B. invadens Drew, Tsuruta & White) in Africa (Kenya).

Status of knowledge

According to Vargas et al. (2015), there are 651 species of Bactrocera worldwide, with at least 50 species of significant economic importance.

Adult taxonomy

Bactrocera Macquart, 1835

Bactrocera Macquart 1835: 452, longicornis Macquart (MO). Attributed to Guerin-Meneville.
Dasyneura Saunders 1842: 60, zonata Saunders (MO). [6600471]
Strumeta Walker 1856: 33, conformis Walker (MO) = umbrosus Fabricius.
Chaetodacus Bezzi 1913: 93, Musca ferruginea Fabricius (OD) = dorsalis Hendel.
Marquesadacus Malloch 1932: 145, Chaetodacus perifuscus Aubertin (MO). Proposed as a subgenus.
Apodacus Perkins 1939: 26, cheesmani Perkins (OD) = cheesmanae Perkins.
Aglaodacus Munro 1984: 18, nesiotes Munro (OD).
Mauritidacus Munro 1984: 25, montyanus Munro (OD).
Bactrocera Guerin-Meneville 1838: 300, longicornis
Guerin-Meneville (MO) = longicornis Macquart. Preocc. Macquart 1835.
Bractrocera Duponchel 1842: 415, missp. Bactrocera Macquart.
Dasyneuba Walker 1849: 1076, missp. Dasyneura Saunders.

 

References

Carroll, L. E., A. L. Norrbom, M. J. Dallwitz, and F. C. Thompson. 2004 onwards. Pest fruit flies of the world – larvae. Version: 8th December 2006. http://delta-intkey.com.

Carroll, L. E., I.M. White, A. Freidberg, A.L. Norrbom, M.J. Dallwitz, and F.C. Thompson. 2002 onwards. Pest fruit flies of the world. Version: 2nd April 2019. delta-intkey.com’

Norrbom, A.L., L.E. Carroll, F.C. Thompson, I.M. White and A. Freidberg. 1999. Systematic database of names, pp. 65-251 & 7,104 records. In ‘Fruit Fly Expert Identification System and Biosystematic Information Database’. (Ed. F.C. Thompson.) Myia (1998) 9: 524 pp. Also Diptera Data Dissemination Disk (CD-ROM) (1998) 1: \names\fruitfly.

Vargas, R., Piñero, J., & Leblanc, L. (2015). An overview of pest species of Bactrocera fruit flies (Diptera: Tephritidae) and the integration of biopesticides with other biological approaches for their management with a focus on the Pacific Region. Insects, 6(2), 297-318.