Pest Fruit Flies of the World – Larvae
Dacus diversus Coquillett, Dacus citronellae Kapoor & Katiyar, Dacus quadrifidus Hendel
Body length 7.5–10mm (range estimated, LEC coded as medium length); slender, elongate, tapering anteriorly (?). Integument unsclerotized, entirely whitish to yellowish. Caudal ridge present. Mature larvae able to jump.
Head. Head of normal shape. Antenna 2-segmented. Stomal organ: primary lobe small, round (?); other peg-sensilla-like structures ?. Stomal region: secondary lobes states 2/3?; sclerotized stomal guards absent (?). Oral ridges present (?); number of oral ridges ?. Elongate, finger-like lobes arising above mandibles absent (?). Median oral lobe ?. Labium broad (?).
Cephalopharyngeal skeleton. Mandibles: subapical teeth present (~Menon et al. (1968)); tooth much smaller than apical tooth, and delicate (~Menon et al. (1968);?); with a single ventral tooth, or with a single medial tooth, or with a single lateral 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 ?.
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 simple.
Anterior spiracles. Anterior spiracle ?. Anterior spiracular tubules ?; 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 29–33µm; slits 3.4–3.7x longer than wide. Dorsal spiracular processes with numerous trunks arising from a short or semicircular base (?; short processes). Number of dorsal spiracular processes 4–8 (~Menon et al. (1968)). Number of ventral spiracular processes 4–8 (~Menon et al. (1968)). Number of lateral spiracular processes 4–8 (~Menon et al. (1968): SPII:4–5, SPIII:7–8). Dorsal and ventral spiracular processes: average number of tips 8–17 (avg. 13.5). Dorsal and ventral spiracular processes: ratio of number of tips to number of trunks 2–4 (avg. 2.5). Area between posterior spiracles smooth.
Host plants. Anacardiaceae, Apocynaceae, Cucurbitaceae, Musaceae, Myristicaceae, Myrtaceae, Rutaceae, Solanaceae.
Brassicaceae: Rhaphanus sp., (Kapoor & Agarwal 1983), dubious record.
Part of plant attacked: fruit, bud or flower other than capitulum (ovaries or young fruit).
Biogeographic region. Oriental.
Specimens examined. Based description and figures of Menon et al. (1968). Note that Menon's figures use a single scale bar for all instars for a particular structure; if scale bars are correct, then instars are incorrectly identified, with his Fig. 5 being second instar rather than first, and figs. 8 and 11 both being third instars. Data on spiracular processes and slit length and length/width ratio may also be questionable, having been taken from his figures, each of which consists of a single rima (redrawn 6 times). The processes seem to have been individually drawn but their arrangement is unusual, suggesting they may have been carelessly cut & pasted (but see SEM's of spp. of ?Rhagoletis).
Sources of data and SEM numbers: 245.
Illustrations. • Cephalopharyngeal skeleton, posterior spiracles.
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’.