Stupkaiella bipunctata (Kincaid)

Curler, Gregory R. & Moulton, John K., 2010, Contributions to Nearctic Stupkaiella Vaillant (Diptera: Psychodidae), Zootaxa 2397, pp. 48-60 : 56-58

Stupkaiella bipunctata (Kincaid)

Pericoma bipunctata Kincaid, 1899: 34 (original description). See Quate 1955: 137 for complete synonymy. Stupkaiella bipunctata (Kincaid) , Vaillant, 1973: 371 (key to Nearctic Stupkaiella ).

Diagnosis. Larva: Postmentum dentate; teeth uniform, conical, arranged in single transverse row. Protuberances of tergal plates and dorsal chaetotaxy of abdominal segments II–VII as described below. Protergal plate on abdominal segments II–VII emarginate anteriorly. Anal division: dorsal sclerite with 2 prominent macrotrichia side by side, inserted dorsomedially, with 2 prominent macrotrichia in line, inserted laterally on both sides; ventral flabellar processes elongate, about six times longer than wide. Pupa: Unknown. Adult: Male eye bridge with 5 facet rows, divided by width of 8.5 facet diameters. Interocular suture inverted U-shaped. Scape three times longer than wide; flagellomere I with 6 spines. Male terminalia: gonostyli with rami of unequal length, dorsal ramus approximately ½ the length of ventral ramus; paramere with dorsal section, dorsal section with lateral processes resembling bat wings. Female terminalia: hypovalvae triangular, with minute median lobe.

Description. Larva ( Figs. 16–26 ): Measurements, instar IV (N = 5) total length 6.30 mm (5.90–6.31), cranial width 0.43 mm. Head capsule broadly ovate, with genae rounded. Antenna composed of 3 digitiform, 2 pyriform, 2 brush-like sensilla. Labrum with multiple clusters of spathiform, pectinate macrotrichia ventrally and multiple setiform sensilla anteriorly. Mandibles and maxilla typical of Pericomini ; prostheca composed of one brush-like and one pectinate macrotrichium. Postmentum dentate; teeth uniform, conical, arranged in single transverse row. Trunk: segmentation and arrangement of tergal plates typical of Psychodinae . Segments I–V parallel-sided, thorax and posterior segments gradually tapered. Integument dark brown to black in color; alveoli moderately numerous, appearing crowded dorsally, smaller, less numerous ventrally; posterior annulus of metathorax, anterior and posterior annuli of abdominal segments II–VII with transverse rows of elongate, brush-like alveoli ventrally; middle annuli of abdominal segments II–VII with patch of elongate, brush-like alveoli between paired, rounded sclerites ventrally. Protuberances of tergal plates and dorsal chaetotaxy of abdominal segments II–VII: protergite with paired, simple protuberances medially; medial protuberances flanked by second pair of simple protuberances; each protuberance with setiform macrotrichium inserted apically; mesotergite with paired, bifurcate protuberances medially; medial protuberances flanked by pair of simple protuberances; each bifurcate protuberance with two setiform macrotrichia inserted apically, each simple protuberance with setiform macrotrichium inserted apically; metatergite with paired, simple protuberances medially; medial protuberances flanked by pair of trifurcate protuberances; each simple protuberance with setiform macrotrichium inserted apically, each trifurcate protuberance with three setiform macrotrichia inserted apically. Protergal plate on abdominal segments II–VII emarginate anteriorly. Anal division: dorsal sclerite with 2 prominent macrotrichia side by side, inserted dorsomedially, with 2 prominent macrotrichia in line, inserted laterally on both sides; ventral flabellar processes elongate, about six times longer than wide.

Pupa: Unknown.

Adult Male: See Quate (1955: 137).

Adult Female: See Quate (1955: 139).

Type material. Syntype [adult male]: U.S.A. WASHINGTON: King Co: Seattle, 11.iv.1898, coll. L.W. Quate; deposited at California Academy of Sciences.

Other records. U.S.A. OREGON: Benton Co: Corvallis, NW 60th Street, 44°35’N 123°18’W, 29.viii.1993, [6 instar IV larvae]; 31.i.1995, [1 instar IV larva]; 31.vii.2007, [5 instar IV larvae], coll. N.H. Anderson, benthic sample; 1–14.vi.2004, [1 adult female]; 1–29.iii.2005, [2 adult female]; 15–28.iv.2005, [1 adult male]; 1–15.v.2005, [1 adult male, 2 adult female]; 16–29.vi.2005, [1 adult female]; 1–14.vii.2005, [1 adult female], coll. N.H. Anderson, emergence trap.

Bionomics. Adults of S. bipunctata apparently begin emerging in early spring (late March?) and continue to emerge throughout the summer, as late as October (one record from British Columbia). Larvae of this species have only been collected in benthic samples taken from one ephemeral stream in western Oregon. It is likely that the larvae were among wet, decaying leaves and mosses.

Distribution. Pacific Coast Ranges. Collected from Oregon, Washington, British Columbia and Alaska.

Remarks. S. bipunctata is the only species of Stupkaiella for which the larva is described. Slide-mounted specimens of a congeneric larva from Great Smoky Mountains National Park differ from the larva of S. bipunctata only by characters of the anal division. Adults of S. bipunctata are most similar to S. capricornuata as males of both species have a sclerotized, sculpted paramere dorsally. Regardless, both species are quite distinct and separable not only by characters, but also by range.

Figures

FIGURES 16 – 22. Scanning electron micrographs of larval Stupkaiella bipunctata. 16. Head capsule, ventral view. 17. Right antenna, ventral view. 18. Details of labrum, ventral view. 19. Details of hypostome and mandibles, ventral view. 20. Details of left maxilla and mandible, ventral view. 21. Details of left maxillary palp, ventral view. 22. Right spiracle, ventral view. Scale bars = 2 µm (21), 10 µm (20), 20 µm (16 – 19, 22). (abbreviations: lr = labrum; md = mandible; mx = maxilla; pstm = postmentum; pt = prostheca).

FIGURES 23 – 24. Scanning electron micrographs of larval Stupkaiella bipunctata. 23. Abdominal segment IV, ventral view. 24. Anal division, ventral view. Scale bars = 20 µm (23), 100 µm (24).

FIGURES 25 – 26. Photomicrographs of larval Stupkaiella bipunctata. 25. Head, thorax and anterior annulus of abdominal segment I, dorsal view. 26. Abdominal segments VI, VII and anal division, dorsal view. Scale bars = 0.3 mm (24 – 25). (abbreviations: pr = prothorax; ms = mesothorax; mt = metathorax; as = anterior spiracle; asVI = abdominal segment six; asVII = abdominal segment seven; ad = anal division; prt = protergite; mst = mesotergite; mtt = metatergite; sp = simple protuberance; bp = bifurcate protuberance; tp = trifurcate protuberance; dfp = dorsal flabellar process; vfp = ventral flabellar process)