Pest Fruit Flies of the World – Larvae


L.E. Carroll, A.L. Norrbom, M.J. Dallwitz, and F.C. Thompson

Bactrocera tsuneonis (Miyake)

Dacus tsuneonis Miyake, Dacus cheni Chao

Japanese orange fly. Body length 12–15mm; slender, elongate, tapering anteriorly, or stout, elongate, tapering anteriorly. Integument unsclerotized, entirely whitish to yellowish. Caudal ridge present (?; need SEM). Mature larvae Miyake doesn't mention jumping in discussion of larval behavior.

Head. Head of normal shape; cephalic lobes moderately developed, or slightly developed. Antenna 2-segmented. Stomal organ: primary lobe small, round (?). Stomal region: secondary lobes present, medial ones elongate, like oral ridges (?); sclerotized stomal guards absent. Oral ridges present; number of oral ridges 9–17 (9–11~Phillips; 17~Miyake; 11+-15~LEC; note: the ridges are bifurcated in longitudinal section); margins entire (from slides). Accessory plates present ~Miyake's desc. Elongate, finger-like lobes arising above mandibles absent. Median oral lobe absent or not protruding. Labium broad.

Cephalopharyngeal skeleton. Mandibles: subapical teeth absent; base elongate, forming a more oblique angle (check again). Parastomal bars elongate, free from hypopharyngeal sclerite. Dental sclerites present, posterior to mandibles.

Spinules and creeping welts. Dorsal spinules on segments T1-T3, or T1-A1.

Caudal segment (a8) and anal lobes. Sensilla on caudal segment 6 or fewer pairs visible (?). Dorsal caudal sensilla obvious, on a single papilla or tubercle (?). Intermediate caudal sensillum I3 absent or visible only with great difficulty (?). Lateral caudal sensillum absent or visible only with great difficulty (?). Intermediate caudal sensilla I1a&b obvious, but not on a papilla or tubercle, or obvious, on a single papilla or tubercle, bifid apically (?). Intermediate caudal sensilla I1a&b and I2 on separate papillae or tubercles. Ventral caudal sensilla absent or visible only with great difficulty (?). Anal lobes plainly visible, but not strongly protuberant; simple (?).

Anterior spiracles. Anterior spiracle elevated, margin concave medially, appearing bilobed. Anterior spiracular tubules 31–34 (34~Phillips; 31–33~Miyake; 32–33~LEC); in a single uniform row, or in a single irregular row.

Posterior spiracles. Posterior spiracular area not distinctly set off from caudal segment. Posterior spiracles: average length of dorsal and ventral rimae 110–130µm; slits 2.5–3.5x longer than wide (range estimated, LEC coded about 3). Dorsal spiracular processes with numerous trunks arising from a short or semicircular base (long processes). Number of dorsal spiracular processes 11–14. Number of ventral spiracular processes 11–14 (?12~LEC). Number of lateral spiracular processes 7–12. Basal width of spiracular processes 13–15µm. Dorsal and ventral spiracular processes: average number of tips 12–27. Dorsal and ventral spiracular processes: ratio of number of tips to number of trunks 1–2.1 (up to 4 per trunk). Area between posterior spiracles smooth.

Host plants. Rutaceae (oranges).

Part of plant attacked: fruit.

Biogeographic region. Palearctic.

Specimens examined. Based on Phillips' specimens from Japan: Kiusiu [=Kyushyu] Island, Sept. 1909, S.J.Kuwana coll. (n=2, NMNH), and on descriptions of Phillips 1946 (as Dacus ferrugineus, misid.) and Miyake 1919 (q.v. for identity of Kuwana specimens).

Sources of data and SEM numbers: coded by LEC from Miyake, Phillips & specimens.

Illustrations. • Cephalopharyngeal skeleton, spiracles, caudal segment. • Cephalopharyngeal skeleton, head, spiracles. • Habitus larva, egg, pupa.

Cite this publication as: ‘L.E. Carroll, A.L. Norrbom, M.J. Dallwitz, and F.C. Thompson. 2004 onwards. Pest fruit flies of the world – larvae. Version: 8th December 2006.’.