[TN-Butterflies] the murky world of duskywings

From: Stephen Stedman <SStedman@xxxxxxxxxx>
To: TN-Butterflies@xxxxxxxxxxxxx
Date: Mon, 30 Mar 2009 13:16:06 -0500
As we enter the time of year that might be referred to as the duskywing
zone, not all that unlike the twilight zone, let me offer some comments
about the genus Erynnis for those folks who wish to report FOY dates for
them and for those more courageous souls who wish to send along
photo-documented first county records.

 

Both Juvenal's and Horace's duskywings fly in spring, though the former
may fly a little earlier than the latter (data on which to base this
comment are thin to almost absent for TN, as far as I know). Each is
tough to separate from the other when only the view from above is
offered, which is usually the case with these spread-winged skippers.
Getting a view of either species showing the hindwing below can be
frustrating, but that is about the best way to i.d. these two lookalike
duskywings; best to wait until you see one nectaring, when it will
usually display its ventral side.  The Juvenal's usually, but not
always, has two fairly prominent spots near the hindwing apex below, and
the Horace's usually, but not always, does not have these.  After late
May or early June, Juvenal's does not fly, so the problem disappears
when the second brood of Horace's arrives on the scene.  Unless you can
get a good view of the hindwing below, it is not safe to turn in records
of either of these species during spring.  Unless you can get a photo of
the hindwing below, it is not likely you can document either species
during spring.  Photos above during summer are fine to document
Horace's.

 

Dreamy and Sleepy duskywing offer a truly difficult i.d. problem; I am
not yet sure how to separate these species in the field or from photos,
and I have been trying for a while.  Anyone who has a foolproof means of
separating the two, which usually fly only during spring, will do such
good service as to cause his or her statue to be set up in a public
butterfly garden.  Well, maybe not that, but I sure will appreciate some
help here, especially if it comes in the form of photos with relevant
comments.

 

Wild Indigo Duskywing is, for me, usually the easiest of the more common
dwings to i.d. with a view or photo above; it looks something like the
Horace's/Juvenal's but is a bit smaller, has a slightly different
outline to the wings, and lacks the prominent spot that is interior to
the four prominent spots near the apex of the forewing above.
Association with crowned vetch is a good hint that what you have is this
species of dwing.

 

Zarucco and Mottled duskywings have been documented for TN, but proving
future records, even with photos, which I have never yet received from
anywhere in TN for either species, will be real interesting.

 

Funereal Duskywing has been reported only once in TN (by Rita Venable);
it is easy to i.d., based on the white fringe on the hindwing above.

 

Good duskywinging, Steve Stedman

Cookeville, Putnam County
[TN-Butterflies] the murky world of duskywings

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