Pacific Northwest Moths

Identification

Adults

Anarta hamata is a mottled, dull gray-tan, medium-sized moth (FW length 16 - 18 mm) that flies in steppe during the summer. It has a dark reniform spot and a two-toned gray-tan and gray hindwing. The tan forewing color is slightly darker gray on the costa, greatest in the anterior subterminal area, and in the terminal area. The basal, antemedial, and postmedial lines are faint gray, double with filling of slightly lighter tan than the ground. The basal and antemedial lines are moderately irregular. The latter line is slightly slanted away from the base and slightly incurved at the posterior margin. The median line is dark gray, but usually faint except on the costa. The postmedial line is weakly to moderately scalloped, often with thin pale and black lines on the veins at the tips of the teeth, drawn toward the base on the costa, gently and broadly excurved around the reniform spot, and bent to join the posterior margin at a slight angle toward the base. The subterminal line is pale ochre-brown, irregular with an offset toward the base below the costa and a strong W-mark on M3 and CuA1 to the outer margin. The line is preceded by dark gray to black wedges on the costa and near the W-mark. The terminal line is a series of dark gray spots between veins that produce a serrate appearance to the base of the fringe. The fringe is tan, sometimes weakly checkered. The orbicular and reniform spots are outlined in thin black. The orbicular spot is round, filled with the ground or slightly lighter brown or gray and usually containing a darker central ocellus. The reniform spot is moderately large, broadly kidney-shaped, mostly filled with smudgy purplish gray. The claviform spot is small and black, occasionally absent, filled with the ground or gray. The hindwing is pale gray-tan with a moderately well-defined dark gray marginal band that usually contains pale spots near the anal angle, dark gray discal spot and veins. The hindwing fringe is whitish tan with a darker tan and yellow base. The head and thorax match the forewing, often with gray transverse bands on the collar. The eye is covered with fine hairs. The male antenna is bead-like.

Anarta hamata is most likely to be confused with Anarta columbica in its steppe habitat. This species is usually significantly smaller (FW < 17 mm) and is darker gray-brown, not tan like A. hamata. The marginal band of A. columbica lacks pale spots near the outer margin. Males of A. hamata can be confirmed by observing the curved tip of the clasper of the left valve after removing the scales from the valves with a small brush; those of similar Anarta species are straight.

Habitat

This species is moderately common in juniper woodlands and open sagebrush steppe at middle to low elevations east of the Cascades.  Moths were more common in juniper-sagebrush habitat that had been burned off by a wild fire two years before.  Thus, this species appears to favor fire disturbance.

Distribution

Pacific Northwest

Anarta hamata is found in the dry interior steppes and juniper parkland from southern British Columbia through Washington and Oregon. It likely also occurs in Idaho.

Global

The range of this species extends to southwestern California and Colorado.

Life History

Larvae

No information is presently available regarding larval foodplants of this species, but it probably feeds on herbaceous vegetation based upon closely related species.

Adults

The flight period of A. hamata is late spring and summer. It might be double-brooded. It has been collected from early May through August. This species is nocturnal and comes to lights.

Economic Importance

None.

Literature

Moth Photographers Group