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Journal archives for July 2017

July 07, 2017

ID Guide 2: Some Mottled Gray Sallows and Daggers

A couple of recently corrected IDs have prompted me to write a long-overdue journal article which covers two extremely similar sallow moths (Noctuidae, Amphipyrinae) and a few other look-alike species. The primary focus of this entry includes:

Grote’s Sallow (Copivaleria grotei): http://mothphotographersgroup.msstate.edu/species.php?hodges=10021

Figure-eight Sallow (Psaphida resumens): http://mothphotographersgroup.msstate.edu/species.php?hodges=10019

Both species occur widely across the eastern U.S. and both are early fliers, primarily from February-April. I’ve recorded both species at my porchlight/blacklight on the same night in mid-March in Central Texas. Both are mottled dark gray Noctuids with paler orbicular and reniform spots and other pale patches. I had previously addressed this ID issue with one of my observations from Feb. 2017: http://www.inaturalist.org/observations/5095885
I also just revised the BugGuide account for Grote's Sallow to include some of the information below.
http://bugguide.net/node/view/15291

Here I recap the ID tricks to separate these two species and add notes about a third species of sallow and one potentially confusable dagger moth. Of course, these are not the only mottled gray and white Noctuids!

For the two species I'm primarily focused on here, four areas should be examined and compared. In descending order of importance, these are:

(1) the pale “arrowhead” at the junction of the FWs in their outer portions (center of the folded wings),
(2) the light-dark contrast on the thorax,
(3) the pale area (if any) on the outer 1/8 of the FWs, and
(4) the relative width of white banding on the tarsal segments (not highlighted on the images).

Here are marked-up examples of each:
Grote's Arrowhead-highlighted
On Grote’s Sallow, notice that the pale central “arrowhead” consists of a small triangular whitish arrowhead, partially set off from a larger, shield-shaped pale area. The latter area commonly has a simple sinuous dark line cutting across it in the forward portion. The upper margin of the shield is generally rounded without sharp outer corners. The thorax, if not worn, is characteristically whitish in the center, with dark “shoulders” (tegulae). The outer 1/8 of the FWs are mottled gray and whitish without a clear pale patch. The white banding on the distal end of each tarsal segment is relatively narrow, taking up << 1/2 of the segment. Something that some individuals of Grote's Sallow have that is absent in Figure-eight is the presence of ochre or gold or olive-brown highlights scattered over much of FWs. This is evident in many images on BugGuide, but a large portion of Grote's lack any hint of those yellow/gold/brown tones and thus are much more similar to Figure-eight.

Figure-eight Arrowhead highlighted
By contrast, the Figure-eight Sallow has a single larger pale arrowhead in the outer portion of the FWs; it has sharp forward corners; there is no “shield” forward of it. The thorax is variably mottled black, gray, and whitish without a pale center; if anything, the tegulae are sometimes paler than the center of the thorax (as in this image from @greglasley). The outer 1/8 of the FWs is commonly uniformly pale gray to whitish, more broadly so toward the inner margins. These terminal pale areas are set off from the pale “arrowhead” by dark “anal streaks”. Each tarsal segment has proportionally wide white banding on it; on several segments, this approaches or exceeds 1/2 of the length of the segment. While the dark ground colors of Figure-eights will occasionally trend toward dark brownish gray, very few individuals show any of the yellow/gold/brown highlights shown by a substantial number of Grote's. Here are a couple of the rare examples (perhaps 3 out of 75) of Figure-eight Sallow showing such highlights:
http://bugguide.net/node/view/496802/bgimage
http://bugguide.net/node/view/94121/bgimage
One Florida example seems to have green highlights (unique):
http://bugguide.net/node/view/96264/bgimage

Another potentially confusing gray sallow is Roland’s Sallow (Psaphida rolandi):
http://mothphotographersgroup.msstate.edu/species.php?hodges=10014
It is also an early flier (Feb-Apr) but Roland's is much more uniform medium to dark gray without any conspicuous pale arrowhead in the middle of the FWs. The orbicular spot is small, almost perfectly circular, and commonly outlined in black; the reniform spot has black forward and rear edges.

Many of the dagger moths (Acronicta spp.) appear in mottled gray tones, but most of them have conspicuous basal and/or anal black streaks or “daggers”. The most similar to the present set of sallows that I’ve encountered in Central Texas is the Afflicted Dagger (Acronicta afflicta):
http://mothphotographersgroup.msstate.edu/species.php?hodges=9254
It shares with Grote’s Sallow the pale center of the thorax, but it has: (a) overall more uniformly dark FWs, (b) a small, conspicuous, circular white orbicular spot, (c) little or no contrast in a gray reniform spot, (d) no obvious or well-marked “arrowhead” in the rear of the FWs (although the area can have some smudgy whitish color), and (e) no obvious pale area in the outer 1/8 of the FWs. It has a much longer flight period from March to September, with a couple of Texas records as early as February and as late as October.

I’d be interested in opinions of other potentially confusable species with this group, particularly for those of us in Texas. I can try to add further information to this post as the need arrises.

Posted on July 07, 2017 22:22 by gcwarbler gcwarbler | 4 comments | Leave a comment

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