Anastrepha crebra Stone, 1942

Rodriguez, Erick J., Steck, Gary J., Moore, Matthew R., Norrbom, Allen L., Diaz, Jessica, Somma, Louis A., Ruiz-Arce, Raul, Sutton, Bruce D., Nolazco, Norma, Muller, Alies & Branham, Marc A., 2022, Exceptional larval morphology of nine species of the Anastrepha mucronota species group (Diptera, Tephritidae), ZooKeys 1127, pp. 155-215 : 155

Anastrepha crebra Stone, 1942

Figs 28-32 , 33-38 , 39-40

Material examined.

Peru • 4 larvae; Madre de Dios, Puerto Maldonado, Centro de Investigación y Capacitacion Rio Los Amigos (CICRA), trail 21; 12.5721°S, 70.0889°W; 232 m a.s.l.; 22 Mar. 2016; N. Zenteno leg.; reared from fruit of Quararibea wittii K. Schumann and O. Ulbrich ( Malvaceae ); FSCA (AP20180315.6-AP20180315.10, AP20180329.08, AP20210415.01) .

Diagnosis.

Anastrepha crebra can be distinguished from other species of Anastrepha , except A. nolazcoae , Anastrepha sp. Peru-82, and Anastrepha sp. nr. protuberans , by the fringed posterior margin of its oral ridges. Anastrepha crebra differs from the latter three species in having fewer oral ridges, a higher number of trunks and tips of the posterior spiracular processes, and shorter spiracular opening length on the posterior spiracle (see Tables 2 - 4 ).

Description.

Habitus. Third instar elongate, cylindrical, tapered anteriorly and caudal end truncate; color creamy; amphipneustic. Length 6.83-7.36 mm and width 1.10-1.21 mm at the sixth abdominal segment.

Pseudocephalon (Figs 28-31 ). Antenna and maxillary palp on moderately developed lobe. Antenna with cylindrical base and apical knob. Maxillary palp bearing three papilla sensilla, two knob sensilla; dorsolateral group of sensilla bearing two well-developed papilla sensilla, aligned at oblique angle to palp and surrounded by collar. Facial mask globular in lateral view. Preoral organ bearing one peg sensillum, located apically on small cylindrical lobe anterolateral to the mouthhook, with two or three adjacent irregular secondary lobes; preoral lobe elongate, broad, extending slightly posterior to preoral organ. Oral ridges in 13-15 rows, posterior margins fringed; accessory plates apparently in one series lateral to oral ridges covering a much smaller area than oral ridges, with fringed posterior margins. Labium narrow, surface channeled medially, ventrally with two visible sensilla on small tubercles.

Cephaloskeleton (Figs 32 - 34 ). Total length from tip of mouthhook to end of ventral cornu 1.08-1.13 mm. Mouthhook well sclerotized, black apically and basally; length a 0.23-0.29 mm; length b 0.16-0.17 mm; height c 0.16-0.20 mm; ratio a:b 1.44-1.71; ratio a:c 1.44-1.45. Tooth long, sharp, strongly curved, concave ventrally with medial carina, ventral surface smooth. Intermediate sclerite 0.18-0.20 mm long, 0.14 mm wide at ventral bridge. Epipharyngeal sclerite visible only in dorsal view, with medial lobe directed anteriorly. Labial sclerite robust, sclerotized, and triangular in dorsal view. Parastomal bar extending three-fourths length of intermediate sclerite. Dorsal arch 0.23-0.24 mm high. Dorsal cornu with well-defined sclerotized area adjacent to notch, 0.42-0.48 mm long. Dorsal bridge projecting anteriorly from dorsal cornu and sclerotized. Anterior sclerite irregularly shaped and sclerotized. Cornu notch (N) 0.36 mm long and cornu notch index (N/DC) 0.75-0.85. Ventral cornu with weakly defined sclerotized area. Pharyngeal filter with weakly sclerotized anterior bar and ridges forming a series of grooves along length of ventral cornu. Ventral cornu 0.62-0.65 mm long from pharyngeal bar to posterior end of grooves. Ventral cornu 1.4-1.5 × as long as sclerotized area of dorsal cornu.

Thoracic and abdominal segments. Thoracic segments with dorsal spinules conical, symmetrical to slightly curved posteriorly; dorsal spinules pattern in rows as follows: T1 with 9-11 rows, forming scalloped plates; T2 with 3-5 rows; T3 with one or two rows; ventral spinule pattern as follows: T1 with 11-15 rows; T2 and T3 lacking spinules. Abdominal segments (A1-A8) lacking dorsal spinules; ventral creeping welts present on all abdominal segments; ventral spinule pattern as follows: A1 with four rows; A2 with 8-10 rows; A3 with 10-13 rows; A4 with 12 rows; A5 with 11-13 rows; A6 with 11 or 12 rows, A7 with 9-11 rows; A8 with nine or ten rows. Additional three anterior and posterior and two lateral irregular rows of spinules surrounding anal lobes, spinules large, conical, distally sharp, pointing away from anal lobes.

Prothoracic spiracle (Figs 35 , 36 ). Bilobed, bearing 16-21 tubules, distally rounded and arranged in a single sinuous row. Spiracle distal width 0.22-0.24 mm; basal width 0.09-0.10 mm at junction with trachea.

Caudal segment (Figs 37 , 38 ). Dorsal (D1 and D2) tubercles and sensilla moderately developed; D1 distinctly anterior to D2. Intermediate tubercles I1 and I2 and associated sensilla moderately developed; I1 ventral to I2. L1, V1, and V2 tubercles and associated sensilla weakly developed. Anal lobe entire and protuberant.

Posterior spiracle (Figs 37 , 39 , 40 ). Located above horizontal midline. Posterior spiracle openings with thick rimae and numerous trabeculae; 58-73 µm long; 21-25 µm wide; ratio length/width 2.8-2.9. Ecdysial scar apparent. Felt chamber oval, 127-135 µm in diameter at junction with trachea. Spiracular process SP-I comprising 14-18 trunks and 33-51 tips; ratio tips/trunks 2.4- 2.8; basal width 20-30 µm; ratio basal width/length of spiracular opening 0.33-0.41. SP-II comprising 5-7 trunks and 11-23 tips. SP-III comprising 8-13 trunks and 21-32 tips. SP-IV comprising 14-20 trunks and 31-39 tips; ratio tips/trunks 2.0-2.2; basal width 16-28 µm; ratio basal width/length of spiracular opening 0.28-0.39.

Distribution.

Anastrepha crebra is known from Mexico, Guatemala, Nicaragua, Costa Rica, Panama, Ecuador ( Norrbom 2004; CoFFHI 2020), and Colombia ( Rodríguez Clavijo et al. 2018). It is recorded for the first time from Peru.

Biology.

This species was reared from fruit of Quararibea wittii , a new host plant record for A. crebra . It has been previously reared from fruits of Quararibea asterolepis Pittier ( Malvaceae ) ( Stone 1942), Quararibea funebris (La Llave) Vischer ( Malvaceae ) ( Hernández-Ortiz and Pérez-Alonso 1993; Aluja et al. 2000), and Quararibea yunckeri Standl. ( Malvaceae ) ( Aluja et al. 2003).

Molecular identification.

COI barcodes were generated from three larvae and three adults submitted to GenBank (MT655069-MT655074). These data further confirm the identity of the described larvae. K2P distances among A. crebra larvae and the 14 available adult sequences (KY428335, MK758576, MK758598, MK759164, MK759601, MK767247, MK767700, MK768011, MK768248, MK768483, MK769383, MK770033, MT655069-MT655071) ranged from 0.0-3.0%. BLAST searches were consistent with our new data, yielding good matches only to A. crebra (97.00-100.00% sequence identity). Additionally, all three larval barcodes returned consensus identifications of A. crebra with three votes ( Moore et al. in press).

Figures

Figures 28 - 32. Scanning electron photomicrographs of third instar of Anastrepha crebra 28 pseudocephalon 29 oral ridges 30 antenna and maxillary palp 31 preoral organ 32 ventral surface of mouthhook. Scale bars: 30 μm (30, 31); 50 μm (32); 80 μm (29); 200 μm (28).

Figures 33 - 38. Optical photomicrographs and scanning electron photomicrographs of third instar of Anastrepha crebra 33 cephaloskeleton, lateral view 34 cephaloskeleton, dorsal view 35 prothoracic spiracle, lateral view 36 prothoracic spiracle, dorsolateral view 37 caudal segment 38 anal lobe. Scale bars: 50 μm (35, 38); 100 μm (36); 200 μm (33, 34, 37).

Figures 39 - 40. Scanning electron photomicrograph and optical photomicrograph of posterior spiracles of third instar of Anastrepha crebra. Scale bars: 50 μm (40); 150 μm (39).