Marble butterfly -- that's the one with green, isn't it?

[rjlittlefield]

To go with MacroLuv's recent postings of various cabbage butterflies, here's a related species from my neck of the woods.

This is one of the Marble whites, Euchloe ausonides most likely.

From a distance, I'd swear that they're green on the underside. "Green, I say!"

Wingspan as mounted, 34 mm.






Of course, I've been wrong before.

They're not green at all. Actually they're kind of black and yellow.

This always surprises me. I mean, sure enough, if you ask Photoshop to average the pixel values in the areas with the dark and yellow scales, you get something that looks sort of olive drab green. It looks just an awful lot like the color in that little "at a distance" image, which matches the real butterfly shockingly well. But if you just asked me, I'd predict that the average would be kinda brownish. Colors -- can't mix 'em, can't match 'em.

These things have an interesting life cycle. They overwinter as pupae, emerge in early spring to lay eggs on wild mustard and rockcress, grow very quickly to get done before the plants dry out, then pupate to wait for the next spring. That is, unless the weather next spring doesn't seem so great, or maybe they just don't feel like coming out then. In either case they wait another year. And so on. Life is tough in the desert. Having different offspring take different shots seems to be a good way to have more of them.

The label on this specimen says "reared on wild mustard in Spring / emerged ~15-IV-96 after 2 (3?) yr pupation". I'm not usually so casual with my labels, but quite frankly I wasn't expecting this pupa to ever do anything and I lost track of which brood!

--Rik

Edit to add technical details. Images 2 and 3 are stacked, 10 and 21 frames respectively.

[beetleman]

Very beautiful butterfly Rik. I have never seen these before not even in books. The pupas must have to slow down their Metabolisms to nothing to stay in the ground for that extra time

[rjlittlefield]

The pupas must have to slow down their Metabolisms to nothing to stay in the ground for that extra time

Not even "in the ground", Doug. These critters pupate above ground, typically strapped to a stem with a girdle of silk around their middle, like shown here at BugGuide. In this area, they're exposed to air temperatures often over 100 degrees F with relative humidity in the 'teens. No eat, no drink, no apparent way to pick up moisture from the environment. Misting not required. The one shown above spent its time in a jar in my garage. How do they keep from drying out? Toward the end, at least, they must exchange oxygen & CO2 with the environment to do their metamorphosis trick. Do they maintain a tight seal for most of the time, then break it down at the end for long enough to finish development? Somebody must have studied this, but I've never read.

In any case, yep, they're quite amazing little critters. Pretty, too.

--Rik

[MacroLuv]

It looks like a textiles fabric. I think I have one of this kind in my archives.

[Ken Ramos]

Beautiful, love the scale shot!