Butterfly Mimics and a Publication Note

butterfly-oct-22
Red-spotted Purple (10/22/16)

On first glance, I thought the butterfly shown above was a late-flying Eastern Black Swallowtail.

swallowtail-june-23
Eastern Black Swallowtail (6/23/16)

After a closer look, I decided the unknown visitor might be a Pipevine Swallowtail. (I don’t have any photos of Pipevine Swallowtails because I’ve never seen one in person. Here’s a link with photos.) But how could it be any kind of swallowtail, without the characteristic “tails” on its hind wings?

Red-spotted Purple (10/22/16)
Red-spotted Purple (10/22/16)

As always, I turned to the internet for answers. Searching for “butterflies that look like Eastern Black Swallowtails” led me to the Swallowtail Butterfly Comparison page on a site called Butterflies at Home. There I discovered that my unknown butterfly is a Red-spotted Purple, which explains why it doesn’t have tails on its hind wings. It isn’t a swallowtail at all. Instead it belongs to the family of brush-footed butterflies. (As an aside, I’m now fascinated with name “brush-footed”.)

Red-spotted Purple
Red-spotted Purple (10/22/16)

But why do all of these butterflies look so similar? What is so special about a combination of blue highlights and reddish spots? Obviously the pattern carries some sort of selective advantage, something deeper than aesthetic appeal for camera-wielding writers.

Unknown Swallowtail July 25
Spicebush Swallowtail (7/25/12)

It seems that the story starts with Pipevine Swallowtails, which lay their eggs on the poisonous pipevine plant (also known as Dutchman’s Pipe.) As the caterpillars feed and grow, they ingest and store a toxin called aristolochic acid, which lingers in their bodies as the caterpillars mature into adults. So the butterflies, as well as all stages of the caterpillars, are poisonous. Even their eggs are poisonous.

All in all, it’s an elegant and effective defense against predators. So effective, in fact, that it conveys a measure of protection for any butterfly with black wings, blue highlights, and reddish spots. Selective advantage, indeed.

butterfly-oct-22
Red-spotted Purple (10/22/16)

Now, if only I could find a Pipevine Swallowtail to photograph…


For more information, check out a few of these articles:


Publication Note: On October 7, my poem “The Fire” posted at Autumn Sky Poetry Daily. Many thanks to editor Christine Klocek-Lim!

More from Red Wing Park (and a Publication Note)

Red Wing Park is one of my favorite places to visit when I crave a short walk. Or when I’m in the mood for butterflies. Yesterday, I discovered several new attractions, including lotus blooms in an artificial pond and a skink basking on the pond’s rock border.

Butterflies were out in droves, even a few species I have never seen before. (Add these to the Snowberry Clearwing Moths in yesterday’s post…)

I caught several images of a large, unfamiliar swallowtail. I can’t tell if these are Pipevine Swallowtails or Spicebush Swallowtails. Maybe both species were present? Any ideas?

One individual had a mangled hindwing, with more than half of the wing amputated. In marked contrast to the other butterflies, this one struggled in flight. It flailed and fluttered along in short spurts, stopping to perch on flowers rather than hovering as it drank. It continued to feed and flirt with its companions, but it was decidedly less agile.

As far as wing injuries go, this was as bad as I’ve seen. I felt an uncomfortable surge of empathy, and I couldn’t help but wonder if the wound was painful. The encounter has turned me philosophical.

It’s just a butterfly. An insect. An ephemeral creature, at best. And yet, its fate affected me. I am reminded of that jaded cliche about chaos theory, the one where a butterfly flaps its wings in one part of the world, causing an alteration in the weather pattern of another part of the world. What of this butterfly’s damaged wing? What currents of change might eddy in its wake?

Publication note:  My poem “The Road” was published at vox poetica this week. It is now posted on the poemblog. Many thanks to editor Annmarie Lockhart!