Photo Forum 2: Suffering with Sulphurs

What's would be your call on this sulphur, photo'd by Jesse Amesbury on Woodcock Trail in Cape May NWR on April 1, 2014?

A hard-to-ID sulphur, photo’d by Jesse Amesbury on Woodcock Trail in Cape May NWR on April 1, 2014.

We could use some help with this one, everybody!

Jesse Amesbury’s photo is our first report of sulphurs of any kind on the log this year, and so it seems a good time to get a discussion going on what is often a very tough distinction in South Jersey: orange sulphur vs. clouded sulphur.

Jesse thought “clouded sulphur” at first, but then had second thoughts and asked for some help, “I would love to learn how to better tell them apart and why the one I saw is what it is.”

What would you call the butterfly above? Clouded? Orange? Sulphur, sp? And why?

No orange is obvious here, but the standard advice, “If you see any orange at all, call it an orange sulphur,” leads to at least a couple of problems. First, fide Jeff Glassberg, that rule is only an “operational definition” (because the two species vary so much and also hybridize). Second, the rule is not much help when you do not see the orange. Not all orange sulphurs show orange — at least in the field.

Comments from anyone would help all of us. So click on “Leave a comment” below and let us hear from you. Even if you do not have a certain call, you could tell us what you focus on as you try to make the distinction. What in the photo catches your eye? (Or: what field marks do you look for when confronted with a sulphur that seems to lack orange?)

Warning: unlike Photo Forum 1 from a couple of weeks ago, this puzzle may have no certainly-correct answer.

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2 Responses to Photo Forum 2: Suffering with Sulphurs

  1. Dave Amadio says:

    My first impression was C.eurytheme(my monitor shows some orange on FW). However the very narrow HW border which shows through in this ventral view suggests C.philodice. In “The Butterflies of North America” by James A. Scott, he mentions that: “short photo-period acting on the third and fourth stage larva produces the spring form ( vernalis ), which is smaller than the summer form and has narrower borders, darker underside HW, and yellow on the outer part of the upperside FW. In the same publication, he cites A.Shapiro saying that ” cold temperature during the pupal stage can also produce vernalis”.

    A great find, being the first sulphur of the year! From this image, I would record it as sulphur sp.


  2. Jim Springer says:

    Distinguishing cool season Orange Sulphurs and Clouded Sulphurs is very tough if not impossible sometimes especially since they can hybridize. Without some indication of what the dorsal side looked like, I would put it down as Colias sp.


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