twirler moth

Scrobipalpula manierreorum is a small twirler moth. It was first described in the Journal of the Lepidopterists' Society in June 2014. It occurs in the northern United States from the Maine west to Minnesota, and in adjacent Canadian Provinces.

The forewing of the adult is ⅛″ to ¼″ (3.7 to 6.5 mm) long and is covered mostly with white scales that have dark brown tips. These scales are intermixed with brown, white, and grayish-orange scales. A broad but diffuse grayish-orange stripe extends from the base of the wing to the tip. The cell has a pair of short, dark brown streaks, one in the middle, one near the end. The fringe hairs at the wing tip have alternating white and dark bands. The legs are striped white and dark.

Adult moths in the genus Scrobipalpula are very similar in appearance. Some, including S. manierreorum, have no external characteristics to identify the species. They can only be distinguished by examining the genitalia under a microscope. The larvae are plant specialists and can be identified by their host plant. The larvae of S. manierreorum mine the leaves of bigleaf aster (Eurybia macrophylla). Adults have been recorded in Alberta and British Columbia, both outside the range of bigleaf aster. This suggests that it may also use other aster species as hosts.

Forewing length: ⅛″ to ¼″ (3.7 to 6.5 mm)

Twirler moth (Scrobipalpula artemisiella) adults are identical in outward appearance. The genitalia are very different, but this can be seen only under a microscope. The larvae feed on field sagewort (Artemisia campestris ssp. caudata).

Spring

Larvae eat only the middle leaf tissues, leaving intact the waxy upper and lower outer layers (cuticles). They create pale tunnels as they eat. The placement and shape of the tunnels, and the presence of frass, are identifying features of leaf miners. Many leaf miner species are plant specialists, and can be identified simply by noting the species of the host plant.

Bigleaf aster (Eurybia macrophylla)

Sources

7, 29, 30, 75, 82, 83.