Cycnia oregonensis tristis Crabo

Crabo, Lars G., Davis, Melanie, Hammond, Paul, Tomas Mustelin, & Jon Shepard,, 2013, Five new species and three new subspecies of Erebidae and Noctuidae (Insecta, Lepidoptera) from Northwestern North America, with notes on Chytolita Grote (Erebidae) and Hydraecia Guenee (Noctuidae), ZooKeys 264, pp. 85-123 : 87-89

Cycnia oregonensis tristis Crabo ssp. n. Figs 1, 32

Type material.

Holotype male, USA, Washington, Thurston County, [WA]DNR Rocky Prairie, 4.2 mi. N of Tenino at Plumb, 46.92°N, 122.85°W, 75 m., 20.VI.1998, L. G. Crabo leg./ Barcodes of Life #CNCNoctuoidea12243. CNC. Paratypes 8 males. USA. Washington. Thurston County: Plumb, N of Tenino, TNC Rocky Prairie, elev 50 m., 46.92°N, 122.85°W, 26.VI.1990, L. G. Crabo leg. (1 male); [same locality and collector], 24.VII.1996; Puget Trough prairie (1 male); Rocky Prairie, 12.VII.1982, Don Frechin leg. (1 male); [same location data and collector as holotype], 4.VI.1998 (1 male); 20.VI.1998 (1 male); 24.VII.1998 (1 male); WA DNR Mima Mounds State Natural Area, 46.907°N, 123.049°W, 240' [73 m.], 4.VI.1998, L. G. Crabo leg., mounded prairie (1 male); Mima Prairie, Thurston County Glacial Heritage Site, 46.86°N, 123.04°W, 120' [37 m.], 10.VII.1998, D. Grosboll leg., prairie (1 male). CNC, LGCC, WSU.

Etymology.

The name is from the Latin tristis meaning sad, a reference to the gray color of this moth and the weather in its western Washington distribution.

Diagnosis.

Cycnia oregonensis tristis is distinguished by the uniform medium gray color of both wings. The nominate subspecies of Cycnia oregonensis (Fig. 2), found elsewhere in North America, has lighter yellow-cream to grayish-cream forewings with lighter veins and nearly white hindwings. Cycnia oregonensis tristis resembles superficially Euchaetes egle (Drury), an eastern North American tiger moth that occurs west to the eastern Great Plains. These moths are easily distinguished by locality.

Description.

Head - Antenna of male moderately bipectinate with each branch covered with fine cilia, black, dorsal shaft covered with light-gray scales. Female unknown. Scape light to medium dark gray with slightly lighter underside. Eye rounded, smooth. Labial palp moderately short with short apical segment, covered by short flat scales except slightly longer at ventral base; basal half yellow and distal half dark gray. Head covered in hair-like yellow scales except inferior and lateral border of frons whitish gray. Thorax - Vestiture of simple hair-like scales, light to medium dark brownish gray, slightly browner than forewing color, anterior portion near head yellow. Prothoracic collar slightly lighter than central thorax, with a gradual transition to yellow on each side. Tegula covered by long hair-like scales, lighter cream than central thorax. Legs: femur of foreleg yellow with gray ventral surface; other femora and the tibiae of all legs slightly brownish gray, smoky gray dorsally and lighter gray ventrally, tibiae lacking spiniform setae; tarsi light tan gray with a slight ochre tint, with three rows of short spiniform setae on each segment. Wings - Forewing length: males 19-20 mm. Forewing nearly even slightly smoky brownish gray, slightly darker on distal third; most specimens with a thin pale streak in fold and approximately half of specimens with veins on distal wing, cubital vein, and 1A+2A similarly pale. Transverse lines and all spots absent. Fringe white with base gray like terminal wing. Dorsal hindwing slightly brownish gray, slightly darker than forewing; half of specimens with slightly paler veins similar to those on forewing, lacking lines and discal spot. Hindwing fringe white with gray base. Abdomen - Color light putty gray with dorsal half of segments I–VI dark orange yellow; with rows of half-round black spots on segments I–VII comprised of a single larger spot in the dorsal midline and smaller rounded spots on lateral abdomen adjacent to lighter venter; ventral segment VII with a bilobed protuberance covered by modified scales (likely for pheromones). Male genitalia - Uncus short, hook-like, evenly tapered to a point, flanked on each side by a large strongly sclerotized block-like process directed posterolaterally with dorsal surface smoothly convex and ventral aspect concave, covered dorsally by innumerable velvety setae. Valve simple, membranous and strap-like, 3 × as long as wide; sacculus modified into a large sclerotized thorn-like process approximately 0.6 × as long and wide as valve, with acute tip directed slightly posteromedially. Aedeagus 7 × as long as wide, mesially constricted, with a pointed narrow cylindrical process arising from ventral aspect of distal third just to left of midline, projecting posteriorly and 20° toward right, and curving slightly dorsad. Vesica approximately 2/3 × as long as aedeagus, curved 90° dorsad from the tip of the aedeagus, with a large elongate conical apical diverticulum directed anteriorly–producing appearance of entire vesica curving 180°-and bearing a small basal patch of short cornuti. Female genitalia - Unknown.

Distribution and biology.

This subspecies is restricted to gravel prairies south of Puget Sound, Washington. These prairies were created by the outwash from the Vashon Lobe of the Pleistocene glaciation, and might have been maintained as open prairies by burning by native humans to promote the growth of camas lilies ( Camassia spp., Liliaceae ) as a food source. The moth is associated with Dogbane ( Apocynum spp., Apocynaceae ), the known foodplant of Camassia oregonensis elsewhere in North America ( Tietz 1972). This is almost certainly the larval foodplant of Camassia oregonensis tristis , although this has not been confirmed. This moth flies during June and July.

Remarks.

Cycnia oregonensis is found in a large part of North America, occurring from coast to coast and from the border with Mexico north to central Saskatchewan and Nova Scotia ( Covell 1984, Ferguson et al. 2000). This range includes much of the PNW, including western Oregon and the area east of the Cascade Range as far north as south-central British Columbia. Throughout most of its range it is nearly uniform in color and pattern. Cycnia oregonensis tristis is limited to a small area near Olympia, Washington and is the only known population of this species in Washington west of the Cascades. It is distinctly grayer and less patterned than all other populations, but has an identical CO1 barcode sequence.

The type specimen of Euchaetes oregonensis Stretch was collected by Lord Walsingham on a trip through Oregon during 1871-1872 ( Stretch 1872-[1874]). Comparison of his itinerary ( Essig 1941) with the flight period of the moth suggests strongly that it was collected in the southwestern corner of the state between Roseburg and the California border. Cycnia oregonensis tristis is separated from the closest west-side populations in western Oregon by 225 kilometers. All of the specimens of Camassia oregonensis oregonensis examined from near the likely type locality are similar to those from elsewhere in North America.

The Puget Prairies where Camassia oregonensis tristis flies are inhabited by several other distinctive Lepidoptera with limited distributions, including the noctuid moth Apamea inordinata olympia Crabo and several uncommon butterflies.