Galgula partita (Wedgling Moth)

This is the little Noctuid moth that I mentioned in 9th night of Moth Week, the one I called the ‘frowny face’ moth. It turns out that it is Galgula partita, and its accepted common name is the wedgling moth. I didn’t think I’d be able to profile these moths because I only got the one photo of it on my sheets, and it flew away as soon as I dumped it out of the container at home. But several hours later I encountered it on one of our windows and was able to recapture it. After spending the night in refrigerated lockdown it was much more cooperative, and after snapping some additional photos I set it free.

These moths are somewhat unusual in that their larvae feed on wood sorrel (Oxalis sp), which is rare amongst lepidoptera, because most of them cannot tolerate the high levels of oxalic acid it contains. Since their coloring is not aposematic I would guess that those toxins confer no defensive advantages. PNW Moths says it is uncommon to rare, which seems odd since Oxalis oregana is nearly ubiquitous in westside forests, and it is certainly abundant in the two locations I recently found this species. Perhaps other moth-ers have the same problem I had with them being very fast and very flighty, and are thus unable to document them.

Description– “Wingspan 20-26 mm…Adult: forewing reddish-brown to grayish in male, shiny dark brownish-maroon to blackish in female; large dark spot on costa, and angled PM and ST lines in both sexes; ST line dotted black in male, dotted white in female; hindwing grayish-brown, darker in female than in male [adapted from description by Charles Covell]” Species Galgula partita – The Wedgeling – Hodges#9688 – BugGuide.Net; also some good photos of females and larvae there

Similar species– Similar colored Udea sp. lack dark spot, have more noticeable reniform and orbicular spots, and the post medial line is irregular; the combination of small size, dark spot between very faint orbicular and reniform spots, and sharply angled and straight postmedial line is unique in our region.

Habitat– “This species is widely distributed in moist forest habitats throughout much of North America. In the Pacific Northwest, it is mostly limited to coastal rainforests of the Coast Range and along the west slope of the Cascades at low elevations, and in mixed hardwood-conifer forests at middle to high elevations in the Cascades. It is usually uncommon to rare.” PNW Moths | Galgula partita

Range– “This species has a wide distribution in wet forests throughout North America as far north as southern Canada in the East and again in British Columbia…This species is found in wet forests in the western part of the Pacific Northwest west of the Coast Range and Cascade Crests.” PNW Moths | Galgula partita

Eats– The larva of this “species is a foodplant specialist feeding on wood-sorrels (Oxalis spp.) in the Oxalidaceae.” PNW Moths | Galgula partita, including Oxalis oregana , Oxalis suksdorfii , and Oxalis corniculata (Creeping Yellow Wood Sorrel).

Eaten by– Presumably a host for parasitoids in Hymenoptera and Diptera, and probably preyed upon by insectivores of all classes, but I can find nothing specific for this species.

Life cycle– Multivoltine, and probably overwinters as pupae, based on its early flight time.

Adults active– “This species is known to fly throughout the year in southern portions of its range. In the Pacific Northwest it has been collected in the spring and fall. It is nocturnal and comes to lights.” PNW Moths | Galgula partita; has peaks in April-early May, mid June-early July, and mid August-late September

Etymology of names– Galgula is probably from the Latin for the name of a woodpecker, but I cannot ascertain what that references. The specific epithet partita is probably from the Latin word for ‘divided’, but I cannot figure out what that refers to either, though it may have to do with the dark patch between the orbicular and reniform spots.