Pest Fruit Flies of the World – Larvae

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

Rhagoletis indifferens Curran

Western cherry fruit fly. Body length 5.5–9.5mm (range estimated, LEC coded as small - medium); elongate-cylindrical (?). Integument unsclerotized, entirely whitish to yellowish. Caudal ridge absent. Mature larvae unable to jump.

Head. Head of normal shape. Antenna 2-segmented. Stomal organ: primary lobe rounded, protuberant; number of peg sensilla one (?); peg sensilla unbranched (?); other peg-sensilla-like structures ?. Stomal region: secondary lobes absent; sclerotized stomal guards present (?); number of sclerotized stomal guards 1 (small, blunt~Kandybina; ?). Oral ridges present; number of oral ridges 5–13 (short; ?); margins entire (?). Accessory plates absent (?). Elongate, finger-like lobes arising above mandibles absent. Median oral lobe absent or not protruding. Labium broad (?).

Cephalopharyngeal skeleton. Mandibles: subapical teeth absent; base stout, nearly perpendicular to a line from ventral part of base to apex of mandible. Parastomal bars elongate, free from hypopharyngeal sclerite. Dental sclerites apparently absent, not visible in lateral view.

Spinules and creeping welts. Dorsal spinules on segments with an unusual distribution (T3-A6?, very hard to see).

Caudal segment (a8) and anal lobes. Sensilla on caudal segment 10 pairs, with at least 7 pairs visible under dissecting microscope (?). Intermediate caudal sensillum I2 obvious (?). Intermediate caudal sensilla I1a&b and I2 on a single tubercle (?). Ventral caudal sensilla obvious, on a papilla or tubercle (?). Anal lobes plainly visible, but not strongly protuberant.

Anterior spiracles. Anterior spiracle elevated, margin convex to straight. Anterior spiracular tubules 7–19 (Blanc & Keifer (1955)); in a single irregular row.

Posterior spiracles. Posterior spiracular area not distinctly set off from caudal segment. Posterior spiracles: slits 2.8–3.5x longer than wide (avg.~Blanc & Keifer; 3.0–3.2~figure as measured by LEC). 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 (?). Number of lateral spiracular processes 8–12 (?). Area between posterior spiracles smooth.

Host plants. Rosaceae (Prunus emarginata & 5 other spp.).

Part of plant attacked: fruit.

Biogeographic region. Nearctic, Palearctic.

Specimens examined. Based on description by Blanc & Keiffer (1955); White & Elson-Harris stated this species is "very similar to R. cingulata and R. fausta. Blanc & Keiffer (1955) studied long series of both R. cingulata and R. indifferens and found (in R. indifferens) the posterior spiracular slits were usually shorter; mean 3.5 times as long as broad. Phillips (1946) recorded other differences not substantiated by Blanc & Keiffer (1955)" This discrepancy is due to Phillips' misidentification of the two species (discussed above).

Sources of data and SEM numbers: 359.

Illustrations. • Anterior spiracle. • Cephalopharyngeal skeleton, spiracles, caudal segment.


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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