Pest Fruit Flies of the World – Larvae


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

Bactrocera tryoni (Froggatt)

Tephritis tryoni Froggatt, Chaetodacus tryoni var. juglandis Tryon, Chaetodacus tryoni var. sarcocephali Tryon

Queensland fruit fly, Qfly. Body length 8–11mm; slender, elongate, tapering anteriorly (?). Integument unsclerotized, entirely whitish to yellowish. Caudal ridge present. Mature larvae able to jump.

Head. Head of normal shape; cephalic lobes well developed. Antenna 2-segmented. Stomal organ: primary lobe small, round; number of peg sensilla three; peg sensilla with many long branches; other peg-sensilla-like structures absent. Stomal region: secondary lobes present, short, leaf-like (6, large); margins of secondary lobes all entire; sclerotized stomal guards absent (?). Oral ridges present; number of oral ridges 9–12 (7–12, mostly 9~Exley 1955); margins scalloped (deeply serrated, bluntly rounded teeth; fringelike). Accessory plates present (small); number of accessory plates 8–12; margins serrated. 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. Parastomal bars elongate, free from hypopharyngeal sclerite. Dental sclerites present, posterior to mandibles.

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

Caudal segment (a8) and anal lobes. Sensilla on caudal segment 10 pairs, with at least 7 pairs visible under dissecting microscope. Ventral caudal sensilla absent or visible only with great difficulty, or obvious, but not on a papilla or tubercle (?). Anal lobes plainly visible, but not strongly protuberant; simple.

Anterior spiracles. Anterior spiracle elevated, margin convex to straight. Anterior spiracular tubules 9–12 (!Exley 1955); 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: slits 2.5–3.5x longer than wide (range estimated, LEC coded about 3). Dorsal spiracular processes with numerous trunks arising from an elongate base (medium to long processes). Number of dorsal spiracular processes 12–17. Number of ventral spiracular processes 12–17. Number of lateral spiracular processes 5–9. Area between posterior spiracles smooth.

Host plants. Anacardiaceae, Annonaceae, Apocynaceae, Arecaceae, Cactaceae, Capparaceae, Caricaceae, Celastraceae, Combretaceae, Cunoniaceae, Davidsoniaceae, Ebenaceae, Euphorbiaceae, Flacourtiaceae, Juglandaceae, Lauraceae, Meliaceae, Moraceae, Musaceae, Myrtaceae, Oleaceae, Oxalidaceae, Passifloraceae, Punicaceae, Rhamnaceae, Rosaceae, Rubiaceae, Rutaceae, Sapindaceae, Sapotaceae, Smilacaceae, Solanaceae, Vitaceae.

Part of plant attacked: fruit.

Biogeographic region. Australasian-Oceanian.

Specimens examined. Based on description by White and Elson-Harris (1992; Australia: Queensland) Rapid diagnostic technique: Dadour et al. (1992) have described two rapid methods for separation of larvae and puparia of B. tryoni from those of Ceratitis capitata, using morphology and electrophoresis; these methods were used to monitor numbers of those flies in the recent Perth eradication campaign (Yeates, 1990).

Sources of data and SEM numbers: 232SEM.

Illustrations. • Cephalopharyngeal skeleton, spiracles, oral ridges, caudal segment. • Cephalopharyngeal skeleton (lateral). • Cephalopharyngeal skeleton, spiracles, caudal segment. • Head (anteroventral) SEM. • Stomal organ SEM. • Head (lateral) SEM. • Anterior spiracle SEM. • Caudal segment (posterior) SEM. • Posterior spiracles SEM. • Caudal segment (lateral) SEM. • Anal lobes SEM.

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.’.