Dacus

Description

Body. Medium to large-sized; body length 8-13 mm; slender, elongate, tapering anteriorly. Integument unsclerotized, entirely whitish to yellowish. Caudal ridge absent. Mature larvae usually able to jump.

Head. Head of normal shape; cephalic lobes moderately- or well-developed. Antenna 2-segmented.

Stomal organ: primary lobe small, round; sometimes with unbranched peg sensilla.

Stomal region: secondary lobes present, medial ones elongate, sometimes those closest to mouth opening resembling small oral ridges; margins of secondary lobes either entire or serrate; sclerotized stomal guards absent. Oral ridges present; number of oral ridges 12-21, usually with some ridges branched. Accessory plates present, sometimes long. Elongate, finger-like lobes arising above mandibles absent. Labium broad.

Cephalopharyngeal skeleton. Mandibles: subapical teeth usually present, variable in size relative to apical tooth; sometimes with a single ventral tooth; base elongate, forming a more oblique angle; mandible with neck. Parastomal bars elongate, free from hypopharyngeal sclerite. Dental sclerites present, posterior to mandibles.

Anterior spiracles.Anterior spiracles convex to flat. Variable amount of anterior spiracular tubules, ranging 14-25; either in a single uniform row or a single irregular row.

Spinules and creeping welts. Dorsal spinules on T1-T3, sometimes extending to A2.

Caudal segment (A8) and anal lobes. Sensilla on caudal segment 10 pair, with at least 7 pair visible under dissecting microscope. Anal lobe morphology unclear, sometimes simple, plainly visible but not protuberant.

Posterior spiracles. Posterior spiracular area not distinctly set off from caudal segment. Posterior spiracles: slits 2.5-4x longer than wide. Dorsal spiracular processes with numerous trunks arising from an elongate base. Processes usually long; number of spiracular processes variable; dorsal spiracular processes range 12-19; ventral processes range 11-18; lateral processes range 3-9. Area between posterior spiracles smooth.

Host plants

Many genera of Cucurbitaceae.

Part of plant attacked: fruit.

Biogeographic region and distribution

Afrotropical

Australasian-Oceanian

Oriental

Palearctic

Adult taxonomy

Dacus Fabricius, 1805

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.

White, I. M. and M. M. Elson-Harris. 1992. Fruit Flies of Economic Significance: Their Identification and Bionomics. International Institute of Entomology, London. xii + 601 p.