Hackberry Emperor—on the Flip Side

February 27, 2009 09:22 AM Filed in: My Garden

On a bright day in early September this little guy was sunning on a windowpane—a sorta dirty windowpane, but I don’t do windows. Besides, a less clean pane is easier to hang onto if you’re a butterfly. He was small enough that I could cover his wingspan with my thumb, but active enough to get my attention by rhythmically alternating his wing position from flat against the glass to folded vertically, and back . . . and forth . . and back . . and forth. Makes you wonder why. Probably a territory display since Emperors are quite territorial and aggressive toward other males. And it may look pretty sexy to cute little females too!

Usually hackberry emperors won’t hold still for a close look, darting off with rapid wing beats and long level glides, alighting almost always in another sunny spot. They have good eyesight and pick up the slightest movement and dart away in the blink of an eye. That’s a good trait to have when birds find you’re a tasty treat!
Always on the lookout for danger from above, who cares about the ground beneath your feet? After all, birds don’t come up from inside a rock or tree trunk, so it is little wonder that I was able to get as close as I wanted from this unique ventral angle.
And this view shows the beautifully patterned underside of the wings. The hind wing shows the row of blue-centered yellow eyespots along the submargin of the wing. The forewing has two eyespots, sometimes only one. The centers of the eyespots appear black here because the blue color is only visible when the sun bounces off the blue metallic-like scales, and we are on the inside, looking out . . and the hackberry is on the outside, looking up, not in!
Can you see the thin white dashes of white on the very outside edge of the wings? Those lines are finger like scales that give the trailing edges of the wings a soft brush like structure that ripples gently as the insect glides. It allows the air passing over the wing to slip off the back edge with hardly any friction or curl as it leaves the wing. This makes for very efficient, almost drag free flight. Modern human aeronautical engineers can see it but have come nowhere near the perfection of this natural marvel of engineering. Well, Mother Nature’s been producing and testing new models and variations for a lot longer than us Johnny-come-latelys.
So, what’s this butterfly look like from a bird’s eye view? Kinda grayish brown with a freckling of white on the outer halves of the wings. Spread out on a rock or tree trunk, you (or a bird) would likely not even see the insect unless it moved, and when it did, it probably would be gone so quick you’d wonder if you really did see it at all. But then, that’s what survival is all about in the deep wilds of the garden.