Pest Fruit Flies of the World – Larvae

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

Bactrocera cucumis (French)

Dacus tryoni var. cucumis French

Cucumber fruit fly. Body length 9–12mm; slender, elongate, tapering anteriorly (?). Integument unsclerotized, entirely whitish to yellowish, or partially sclerotized (rarely & then in mature larvae); sclerotization forming a transverse line beneath posterior spiracles (mature larvae); sclerotized process(es) on caudal segment absent. Caudal ridge present. Mature larvae able to jump.

Head. Head of normal shape; cephalic lobes well developed, or moderately developed. Antenna 2-segmented. Stomal organ: primary lobe small, round; number of peg sensilla two, or three; peg sensilla unbranched; other peg-sensilla-like structures absent. Stomal region: secondary lobes present, medial ones elongate, like oral ridges (6–8, large, resembling short oral ridges); margins of secondary lobes more than one lobe with serrate margins; sclerotized stomal guards absent (?). Oral ridges present; number of oral ridges 14–20 (12–17~Exley 1955); margins scalloped (large, deeply serrated, bluntly rounded teeth). Accessory plates present (elongate, large, interlocking with outer edges of oral ridges); margins serrated. Elongate, finger-like lobes arising above mandibles absent. Median oral lobe absent or not protruding. Labium broad.

Cephalopharyngeal skeleton. Mandibles: subapical teeth present; tooth much smaller than apical tooth, and delicate; with a single ventral tooth (?); 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 13–19 (12–19~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 (long processes). Number of dorsal spiracular processes 9–15. Number of ventral spiracular processes 9–15. Number of lateral spiracular processes 4–16. Area between posterior spiracles smooth.

Host plants. Caricaceae, Cucurbitaceae, Euphorbiaceae, Passifloraceae, Solanaceae.

Part of plant attacked: fruit.

Biogeographic region. Australasian-Oceanian.

Specimens examined. Based on description by White and Elson-Harris (1992; Australia: Queensland).

Sources of data and SEM numbers: (Austrodacus)171SEM.

Illustrations. • Cephalopharyngeal skeleton, spiracles, caudal segment. • Cephalopharyngeal skeleton (lateral).


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. http://delta-intkey.com’.

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