Thursday, January 5, 2012

The Luna Moth: A Photo Essay

One of my goals for this past summer was to find as many moths in the family Saturniidae as I could. The saturniids are the moths that give moths great publicity: they're huge, they're colorful, and they make their presence known. In fact, this family includes North America's largest native moth: the Cecropia moth.

The Cecropia moth: Hyalophora cecropia. With a wingspan of up to 6 inches, it is a HUGE moth.

I was out at the Barbara A. Beiser Field Station often during the summer, and on my first day there, in late May, I struck gold. As I knelt down to examine a Clubtail dragonfly (Gomphus sp.), I heard a strange rustling in the grass nearby. I took a few quick snapshots of the dragonfly and turned around to see what was causing the ruckus. I could hear it, but due to the dense, wet, matted grass, I couldn't quite find it. 

And then I saw it.

But...what was it, exactly? My eyes darted around, surveying the yellow, white, and maroon mass crawling towards me. At first, it looked like two beetles wrestling and falling through the undergrowth. Confused, I took a closer look and realized what was actually coming at me.

Trust me, that totally looked like two beetles when I first saw it.

Full of glee, I realized that I was looking at a Luna Moth (Actias luna), one of the saturniids I was searching for! However, it did not look like what the Lunesta commercials had led me to believe what a Luna moth looks like. First of all, it did not glow. Secondly, its wings were shrunken, and the abdomen looked distended.

Not yet ready for flight.

There could be only one explanation: this individual had just emerged from its pupa! That's even more exciting than finding an adult flying around! I knew then what I had to do.

 Need a hand?

To avoid accidentally stepping on it, I picked it up and placed it on a nearby maple tree.

That's not quite what you're used to seeing from a moth, huh? The abdomen was bulging with that green stuff, which I assume is hemolymph that it was planning to use to pump up its wings.

Notice the antennae and how plumose they are: that indicates a male. The males need huge antennae to pick up the pheromones of the females, a surefire way to find a mate!

After placing it safely upon the tree, I waited. Not wanting to waste all day watching a Luna Moth pump up its wings (it's like watching paint dry, but more beautiful), I went along to find assassin bugs and other marvelous insects, returning at times to check up on my Luna Moth.

After three minutes of being on the tree, the Luna Moth has already set to work! You can see the wings are starting to flare out and enlarge, while the abdomen has contracted a great deal. It's becoming much more plump and much less thin. 

Just nine minutes later and the wings are hanging like trendy curtains. The eye spots on the forewings give it a look akin to the face of a wrinkly old man.

15 minutes later and you can definitely see the face of an old man. The eye spots have really come out now. Speaking of which, have you ever wondered what those eye spots look like under a microscope? Or, where the term "Lepidoptera" (the name of the order that includes the moths and butterflies) is derived from? Well, thanks to Wikipedia, your questions can now be answered!

This picture by Peter Znamenskiy shows what those eye spots really look like. You see, "Lepidoptera" is derived from the Ancient Greek words lepís and pterón, the words for scale and wing. Put those words together, and you get an order of insects that have scales on their wings. Those colorful structures that look like paintbrushes are the scales, and they give this moth its awe-inspiring colors.

20 minutes later, and we return to the Luna moth. The abdomen is now obscured by the wings, so we go in for a side view. Yep, that is one plump abdomen. But what's this? The hind wings look a bit wonky. You didn't forget that moths have two pairs of wings, right?

30 minutes in, and the moth seems to be imitating a butterfly: its wings are held above the body vertically, rather than horizontally. What gives? Well, he still has a second pair of wings to pump up, wouldn't it be easier to do that without the first pair holding them down?

After 35 minutes, it looks like the second pair of wings have a comma at the end. They probably need to pause before they finish their sentence.

Well how about that? At 55 minutes, the hind wings bring with them some nice streamers. The Luna moth is ending its sentence with an exclamation point, for sure!

He's still working hard at 1 hour and 15 minutes. Art takes time, after all.

After 1 hour and 40 minutes, you might be asking yourself: "What's with the streamers? Is the moth going to throw a fancy party?" The answer to that question is yes and no. Here's the reason for answering no: The hind wings also have eye spots, and combining the eye spots and the tapering ends of the wings might be just enough to confuse a predator (such as a bird) into aiming for the rear quarters of the moth, rather than its head. If the bird grabs the streamers, the moth still has a chance to get away. Now, why is the answer also yes? Well, the adult Luna moth does not eat. Therefore, it only has a lifespan of about one week. Due to this, the adult Luna moth lives its adult life like it's one big party. Its sole raison d'être is mating, and it devotes itself to this debauchery at full throttle. If it doesn't pass on its genes, it has literally failed at life, hence why the males have such big and sensitive antennae. If you pick up the female's pheromones, you win the game of life.

2 hours and 10 minutes later, the moth is still preparing for his fancy party: putting up streamers, acting chill, and making sure he looks good for the ladies.

Finally, after 3 hours, he's......still not ready for that fancy party. I, however, am famished. After about 7 hours at the field station, I must head out, eat, and rest. 

I loitered around for as long as I could, but I could not stay and watch the Luna moth finish up. It was fascinating to watch it progress from stumpy little cushions to bona fide tapering wings, and I found a new appreciation for these Moon moths. This was definitely a check on my list of saturniid moths I needed to see. 

So, as I often say, if you think Ohio's diversity of insects is nothing to praise, think again!


  1. Awesome! Talk about perfect timing on a perfect subject! Great post and photographs, Derek. I've never had the pleasure of seeing one of those beauties unfurl its wings and just consider myself lucky to bump into one flying or resting from time to time.

  2. Wow! This I have never seen. I've seen Luna Moths but never one unfolding and pumping up. Amazing!

  3. Wow! I would have been thrilled to see and photograph such a beautiful experience!! Great post and photos!!

  4. A-MA-ZING!!!
    That is truly a once-in-a-lifetime event! You are a lucky guy! Thanks for taking and sharing such great photos!

  5. Thanks for all the compliments everyone! It definitely turned out well. Maybe I can get a repeat with a Cecropia moth this coming summer...

  6. i absolutely loved this. i had no idea what was happening. and i only came to this site for a picture. but your story grabbed a hold of me. thank you so much for narrating and sharing this beautiful journey with us.

  7. This was a wonderful trip through time. I loved seeing the wings expand just as much as I love watching dragonflies emerge. Is there a predation threat from putting the moth on the tree? Would it have normally stayed in the brush? Do they go through metamorphosis in the soil?

  8. The predation threat is the highest when the moth is on the tree, but it's necessary. It needs a vertical surface to hang from while expanding its wings, otherwise there's a higher chance of damage if it tries to do it on the forest floor. I checked back on it for a while and it was fine though, so I have a good feeling that it flew off without being eaten. They do go through their metamorphosis in the soil--here's a picture of what they look like during that phase: And it was only going through the brush to find a vertical surface after emerging from the soil.

  9. Actually, lunas do not go through metamorphosis in the soil. The caterpillar makes a cocoon using silk and a leaf or two. Your moth's cocoon would have been in the leaf litter somewhere around you.

  10. You're right KC, I just checked that and I'm wrong. I wish I had known that at the time, I could have looked around for its cocoon!

    1. If you need any more answers, I'll be the tallest guy at Mothapalooza. :D

  11. Wow, this is truly amazing! Thank you for sharing this beautiful moment :)


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