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 fausta (Osten Sacken)

Trypeta fausta Osten Sacken, Rhagoletis intrudens Aldrich

Black 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; cephalic lobes moderately developed (?). 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 2 (large). Oral ridges present; number of oral ridges 3–6; 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 present; tooth smaller than apical tooth, and very stout; with a single lateral tooth; 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 T1-A7, or T1-A8.

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 very protuberant, or plainly visible, but not strongly protuberant.

Anterior spiracles. Anterior spiracle elevated, margin convex to straight. Anterior spiracular tubules 16–19 (~~); in a single irregular row, or in two rows (?).

Posterior spiracles. Posterior spiracular area not distinctly set off from caudal segment. Posterior spiracles: slits 3–4x longer than wide (3.1–3.9~figure as measured by LEC, but check spec.). Dorsal spiracular processes with numerous trunks arising from a short or semicircular base (long processes). Number of dorsal spiracular processes 8–12 (range estimated, LEC coded 10). Number of ventral spiracular processes 8–12 (range estimated, LEC coded 10). Number of lateral spiracular processes 6–8 (? Phillips figure). Area between posterior spiracles smooth.

Host plants. Rosaceae (Prunus emarginata (w. USA), P. pennsylvanica (e. USA), and 5 other Prunus spp.).

Part of plant attacked: fruit.

Biogeographic region. Nearctic.

Specimens examined. LEC based on specimens of Phillips (1946): Ithaca, N.Y., C.U. lot 400 s[ub] 3 (n=2; the other 2 specimens of "fausta" lack subapical teeth & are cingulata) and specimens identified by her as "cingulata" (C.U. lot 400 sub 3 (n=1) and sub 2 (n=6)) but which have subapical teeth & 2 large stomal guards; All the "cingulata" CPS, AS, & PS figures were from these latter specimens, not from the teneral specimens of cingulata which appear to have been correctly identified. This conclusion is in agreement with figures by Frick et al. (1954) and Peterson (1960), and explains the discrepancy in numbers of AS tubules described by Phillips with the results of Blanc & Keifer (1955).

Sources of data and SEM numbers: as described by LEC 7.v.96.

Illustrations. • Mandible. • Cephalopharyngeal skeleton, spiracles. • Caudal segment (posterior & 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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