rigid sunflower borer

not listed

N5 - Secure

SNR - Unranked

not listed

Rigid sunflower borer is a mid-sized, late season, borer moth. It occurs in the United States from New Hampshire to northern Virginia, west to Minnesota and Iowa, and south along the Appalachian Mountains to North Carolina. There is a single record of it in Oklahoma, far outside of its known range. It also occurs in southern Canada from New Brunswick to Ontario. It is not common in Minnesota.

The larvae feed on the leaves of sunflowers and related species, including Jerusalem artichoke, paleleaf woodland sunflower, thinleaf sunflower, common sneezeweed, golden alexanders, and smooth oxeye. Adults are active from August to October, though individuals have been reported as early as late July. They are found in meadows and woodlands where its food plants grow.

Rigid sunflower borer was common in the northeast and Midwest as recently as the 1970s. Its numbers have been seriously reduced due to overgrazing of its host plants by deer.

Adults have a 1¼″ to 17⁄16″ (31 to 36 mm) wingspan. The ground color is pale straw yellow.

The head is mostly purplish gray, but it is straw yellow on top.

On the upper side of the thorax, there is a loose tuft of hairs and a pair of hair-covered, scale-like plates (patagia) that cover the wing bases. The tuft and the patagia are purplish.

The forewings are moderate sized and triangular. Each forewing is pale straw yellow with heavy brown speckling from the base to the postmedial (PM) line. Beyond the PM line it is shaded purplish brown except at the wingtip, where it is straw yellow. There is also purplish-brown shading above the antemedial (AM) line. The AM line is vaguely W-shaped. The inner, downwardly pointing lobe is short and rounded, and the outer lobe is long and is sharply pointed. The median line is brown and W-shaped. The PM line is slightly curved to almost straight, not wavy. The AM and PM lines are dark brown, bold, and doubled – there is an indistinct, lighter brown line beyond the AM line and another before the PM line. The subterminal (ST) line is dark brown with a crescent-shaped lobe between each vein. The shading beyond the ST line is often slightly lighter. There are two spots (orbicular spot and claviform spot) in the upper median area and a kidney-shaped spot (reniform spot) in the lower median area. Each spot is bordered with a dark brown line and is filled with the ground color, not with white.

The hindwings are pale yellowish, almost white.

Wingspan: 1¼″ to 17⁄16″ (31 to 36 mm)

Meadows and woodlands

One generation per year: August to October

Adults rarely venture far from their host plants. They will come to lights but only if those lights are placed near their host plants.

Leaves of sunflowers and related species, including Jerusalem artichoke, paleleaf woodland sunflower, thinleaf sunflower, common sneezeweed, golden alexanders, and smooth oxeye.

Flower nectar

Sources

4, 21, 29, 30, 75, 82, 83.

Not common

Papaipema rigida (rigid sunflower borer)

I've only seen them on the undersides of sunflower leaves, in this case, a native prairie sunflower. Photos taken at Barnes Prairie, Racine Co., WI on August 31, 2020.

Location: Barnes Prairie, Racine Co., WI

I've only seen them on the undersides of sunflower leaves, in this case, a native prairie sunflower. Photos taken at Barnes Prairie, Racine Co., WI on August 31, 2020.