Tuesday, May 27, 2014

variable checkerspot ~ 05/27/14 ~ Pinnacles

variable checkerspot / chalcedon checkerspot
(Shapiro and Tenney)

I'm determined to learn the local butterflies like the back of my hand, but distinguishing look-alike spp. can sometimes trip me up.  Identifying photos is very different than identifying them on the wing, and I want to improve my skills for both methods.  Several have argued with me that it is impossible to tell sp. based only on a photo.  Hogwash.  I'll admit, I want to disprove the detractors, but I could end up being completely wrong.  It certainly helps as I do this exercise that I have the added benefit of having watched the live butterfly and am focusing primarily on one location through the season.

I'm of the belief that it simply takes a differently trained eye to ID photos compared to the traditional examination of a series of pinned and spread specimens.  Emphasis on trained.  I've noticed the classic lepidopterists will most likely describe the topside view of the butterfly as they're most predominantly pinned and spread, compared to what's actually seen out in the wild.  I tend to capture pictures of the underside with the wings held up above the body.  So, guess which side needs to get the description for diagnostics as we transition from specimen identification to photo identification?  

From what I can tell from my photos, both variable above and Edith's look like the underside forewing's 3rd-4th row from the margin have 2 distinct patterns.  I would have thought the two above might be sexually dimorphic with the female facing left, but it can't be.  You know why?  The going assumption is that only male butterflies mud-puddle.  Seriously.  FYI, the only females in our area that are known to mud-puddle are CA sister.  So, we presumably have two males above.  Check.

I have to say, I really want the 2nd photo facing left and the redder of the two to be Edith's.  Red flash = red underside FW.  Nope.  Glassberg says in his west binoc book that Edith's "always lack white, off-center abdominal spots that variable checkerspots sometimes have."  Indeed, there are obvious off-center abdominal spots evident in both pictures.  Just to make sure the local ssp. of Edith's might not break that rule, I double-checked with Art and Paul J.  They both confirm that they believe the two individuals shown above are E. chalcedona, not E. editha, primarily by overall gut feeling.  Paul says, "Around here, variable always* has those spots, and Edith's always has orange rings.  *Always = unless the individual is very worn and the spots/rings are gone.  Remember, these comments apply to the top half of the abdomen."  Art also uses the all-orange antennal bulbs as indicators of variable like I do.  I've noticed shading is often present, and sometimes it's a judgment call if they're considered black like in Edith's.  Also, note the white stripes on orange antennal stems, not white stripes on black antennal stems like in Edith's.

Really, out in the field, there's a third way to describe what's seen as the butterfly is in flight.  Flashes of color will often present themselves that are not obvious from a still photo of either the top or bottom sides.  Variable at Pinnacles flash black and lemon yellow to me.  Edith's flash reddish-orange checks.  Sigh, I know this seems like a lot, but I want to make sure I have my basics down pat.


Imperfect and Tense said...

Mmm, that's a gorgeous butterfly. I hear what you're saying re photo ID and undersides of wings. On a recent holiday, we spotted a Pearl-bordered Fritillary, Boloria euphrosyne (though it could've been a Small Pearl-bordered Fritillary, Boloria selene). They look very similar, live in the same habitats and are on the wing at pretty much the same time. The easiest way to distinguish between the two is by looking at the undersides of the hind wings. Sadly, my photos did not capture enough underside detail, so I had the more difficult job of using the upper sides to make the ID.

Katie (Nature ID) said...

I remember the moment when I first discovered butterflies look very different topside vs. underside. I'm worried my best photos may be useless for ID purposes. We'll see.