Cecropia Moth: the Life Cycle of the Largest Moth in North America

It was a heat spring day in Asheville, North Carolina. I used to be yanking invasive English ivy off a few of my bushes after I noticed an enormous brown cocoon connected to the trunk of a giant cherry tree, solely about 4 toes up from the bottom. I might inform it was a moth’s cocoon nevertheless it appeared far too massive. It was so long as my fist from high to backside, almost 4 and a half inches lengthy! What huge creature was tucked away in right here ready to emerge? After a little bit of analysis and loads of wishful considering, I made a decision this have to be a Cecropia Moth, the biggest moth in North America. I used to be thrilled! I had by no means seen one earlier than in my life.

Butterflies appear to get all the eye. That’s as a result of they’re flying round within the sunshine and we are able to get take a look at them. (Study the right way to make a butterfly backyard!) But it surely’s their cousins on the ‘darkish aspect’ who’re the actual champions of range: the moths.

Out of all of the Lepidoptera (the order of butterflies and moths) solely 10% of species are butterflies, 90% are moths! Actually, there are greater than 11,000 species of moths simply in North America (with over 160,00 described moth species around the globe!) This wonderful range of North American moths features a beautiful array of lovely, colourful, and generally weird animals. Together with the most important of all of them: Hyalophora cecropia, generally known as the Cecropia Moth (or Robin Moth, or Cecropia Silk Moth, or Big Silk Moth).

I already liked moths, and had seen a few the most important moths in the US, together with an enormous Luna Moth simply someday earlier:

And a Polyphemus Moth which might be the second largest moth in North America. The wingspan will be as much as 150mm (virtually 6 inches!) which makes it virtually a tie with the Cecropia.

I used to be tremendous excited on the prospect of lastly seeing the largest moth on the continent. So I waited. 

However truthfully I had no concept if the pupa was even viable. Perhaps it had been parasitized and died? Perhaps it was left over from a earlier yr? And even when it was nonetheless alive, the right way to catch a wild moth rising from the cocoon? I might have ripped it off the tree and introduced it inside and put in a cage and waited, however I hate to disturb wild animals for my very own egocentric functions.

So as an alternative I left it in place and considered a less-invasive plan. First I arrange one among our path cameras (a Bushnell Natureview HD) and pointed it on the cocoon. Simply in case I missed the entire thing, I’d get some video clips so I might see what occurred.

Secondly, I fantasized about establishing a movement detector to alert me when one thing moved. I steered this concept to Cristina and she or he rolled her eyes so onerous that she truly damage her eyeballs (This isn’t an exaggeration, she truly stated “ow”.)

I used to be considering one thing just like the Superb Safety SK602G Movement Detector package as a result of it’s pretty low cost (about $25), weatherproof, runs on batteries, and is wi-fi. I might mount one pointing on the tree after which put the alarm unit inside my home, for the reason that tree isn’t too far-off. I might select one of many much less offensive sounds just like the “gentle chime” setting, and simply wait. Sadly, I didn’t go for it. So I don’t know if it will have labored. But when I do strive it on one thing else I’ll remember to make a publish about it and allow you to know. As a substitute we opted for the great quaint “keep watch over it” methodology.

Every week into June I began to worry that the pupa was lifeless and perhaps I ought to reduce it open to see. However I needed to give it extra time simply in case. Then, on June ninth, Cristina and I have been visiting the vegetation in my native woodland flower backyard when Cristina stated to me, “Have you ever checked on the cocoon these days? Why is it turning white?” I glanced at it and realized that the little bit of white was truly the sting of a wing. I shouted, “Holy shit, it’s out!” and instantly turned and ran full pace to the home for my digicam. It was a Cecropia moth alright. I couldn’t consider it. Cristina had greater than made up for her eye-roll by being my cocoon alarm. However earlier than we check out this big moth, a fast look again at her life: the cecropia moth life cycle.

In mid June of final yr she was only a tiny egg on a leaf in a cherry tree. Inside two weeks (round late June) she hatched out of her little egg as a tiny larva (the larva of a moth or a butterfly known as a caterpillar). She ate the egg shell that she had simply hatched from as her first meal, after which began consuming the leaf beneath her. She in all probability had 8 to 10 brothers and sisters rising from different eggs on the identical leaf who additionally began munching. She could have had a whole lot of different brothers and sisters rising from their very own eggs on different leaves within the space. As a cecropia moth caterpillar, her job is to eat and eat and develop and develop. Over the course of a couple of month, she’s going to shed her pores and skin 4 instances as she grows. Every time she sheds her pores and skin (or “molts“), she enters a brand new stage known as an “instar“.

Caterpillars have 5 instars. Every instar seems somewhat totally different from the earlier one and solely lasts a couple of week. She began out in her fist instar as a tiny, black, spiky caterpillar. After molting into the second instar she had a yellow physique, however the the spikes have been nonetheless black. As a third instar larva she was even brighter yellow and her spikes had become knobby protrusions known as “tubercles”. These tubercles have been brightly coloured; some have been yellow, some have been aqua blue/inexperienced, and a few have been vibrant pink, however they nonetheless have black spines on high! After molting once more and rising as a fourth instar caterpillar her pores and skin was a light-weight inexperienced and she or he grew larger and longer and fatter as she ate and ate and ate.

Lastly she molted into her fifth instar, a ravishing deep leafy-green coloration, nonetheless lined with brightly-colored tubercles of yellow and blue and pink. By this level she was an enormous caterpillar about 4 inches lengthy!

She will be able to spin silk as a result of she is a silkmoth, a member of the Saturniidae household. Inside this protecting layer she spun one other silky enclosure round herself. Between the 2 layer she made a wispy silk stuffing to insulate her in the course of the lengthy winter forward.

After about 10 days inside this cozy mattress, in all probability a while in early August, she shed her caterpillar pores and skin one final time, and emerged as a pupa, a good little bundle the place her physique undergoes a radical transformation.

For the following ten months she waited in her cocoon. Camouflage is necessary at this stage to guard her from predators. Grey Squirrels will generally hunt for the pupae of the enormous silkworm moths (the Saturniidae) and based on one research they appear to have the ability to inform the distinction between residing and lifeless pupae. A really chilly winter handed by with many freezing nights.

In spring, some ivy grew up round her however she remained protected inside. When the times started to get sizzling in Might her transformation to an grownup moth was coming to an finish. That’s after I first noticed her cocoon. A month later in early June, after a number of days of heavy rain, the time was proper to emerge.

On June ninth, early within the morning earlier than dawn, she started to push her manner out of the outer pores and skin of her pupa stage. That is known as eclosion. Because the pupal case cut up she pushed upward via a small “escape hatch” on the high of the cocoon. She squeezed via the tiny opening, pulled herself free, and emerged as a ravishing grownup moth.

She climbed up the tough bark just a few inches and commenced to pump fluid into her wings to increase them. A number of hours later they’d virtually reached their full magnificent dimension, however they have been nonetheless somewhat wrinkly. That’s when Cristina and I noticed her round 12:30 within the afternoon and I virtually pooped my pants.

It was so superior to get a close-up take a look at this big insect. The colours and patterns on her enormous wings have been spectacular. There have been some stunning “eye spots” which may also help to distract predators by mimicking a big face (very like the owl butterfly of Central America.)

However I believe essentially the most stunning factor is her physique. These enormous furry pink legs appear to be they might be extra at house on a tarantula than on a moth! And the attractive, soft-looking “fur” on the large stomach has much more stunning colours and patterns! Wow!

As an grownup feminine cecropia moth, her solely purpose now could be to mate and lay eggs. As a result of cecropia moths aren’t very considerable, it may be a problem for men and women to seek out one another. So how do they do it? The feminine mainly holds nonetheless and sends out highly effective chemical indicators in a single day known as pheromones. The male detects them along with his giant antenna over huge distances (some say over a mile, although that is tough to show scientifically) and often finds her simply earlier than dawn.

Cecropia moths don’t have any practical mouthparts or digestive tracts! They can’t eat! That’s why grownup cecropia moths solely reside about 10 days (perhaps 2 weeks on the most). They need to survive off of vitality saved up from the caterpillar stage virtually a yr earlier! Time is of the essence right here. They should discover one another and mate earlier than it’s too late.

So I checked on her all through the remainder of the day whereas her wings hardened. Because the solar started to set I knew she was about to start out pumping out pheromones to draw a mate. Good luck stunning moth!

Now I had an opportunity to watch the variations between a male and a feminine cecropia moth. The primary apparent distinction was the antennae. Males have giant, feathery-looking antennae which can be used for detecting the pheromones of the feminine. The feminine antenna are of comparable size however thinner.

The second apparent distinction is that the feminine’s stomach is far bigger as a result of it is filled with eggs. I had learn someplace that male cecropia moths have been larger than females, however that positively wasn’t the case with these two. Not solely was her stomach a lot bigger however her wings appeared to be bigger than his as properly.

I additionally seen that the male had a big chunk taken out of one among his wings. Even along with his harm he nonetheless managed to seek out his strategy to her. I snapped a pair images and left them to their enterprise.

Round 10 am I went to verify on them and I seen the male appeared agitated. On nearer inspection I seen that somewhat slug had discovered his manner up onto the again of the male cecropia moth! He began frantically attempting to wipe the slug off himself however couldn’t attain it. I needed to assist but additionally didn’t wish to scare him off by poking him. So I ran inside to enlist Cristina’s recommendation and assist (she’s just like the insect emergency room round right here). However by the point we bought again out he had managed to dislodge the slug. Whew! Again to enterprise. You’ll discover within the picture beneath that he closed up his enormous antennae in the course of the slug incident!

They mated all day lengthy, from dawn (I presume, I didn’t catch the start) till an hour previous sundown. I checked at 9pm (quarter-hour after sundown) they usually have been nonetheless collectively. I went out once more at 10 pm they usually have been each gone. Maybe the male went on to search for one other feminine earlier than his time was up. In the meantime, our feminine was taking her first flight in search of an acceptable place to put her eggs. We by no means noticed her once more however I hoped she was within the bushes above me laying a whole lot of eggs and beginning the method over once more.

I don’t have excessive hopes of recognizing her caterpillars as a result of they might be in any one among dozens of species of potential host bushes. Among the favourite cecropia host vegetation are maples and cherry bushes and now we have loads of each. (One supply lists over 75 species of host bushes the place they’ll lay their eggs!) I’m simply completely happy to know she succeeded and the following era has begun! Hopefully I’ll uncover extra cocoons in one other month or two!

With a restricted time to reside (solely about 10 days) and a restricted quantity of vitality to spend on her process (mating and laying eggs) I didn’t need her to waste any of that vitality by forcing her fly away in worry or drop to the bottom in a defensive response (one thing giant silk moths could do). Keep in mind, she can’t eat to recapture that vitality! I’ve learn that these moths are fairly docile and will be dealt with by people with out an excessive amount of stress, however I most well-liked to take the respectful route and go away her alone.

So as an alternative I got here up with a less-invasive strategy to measure this unimaginable animal. I photographed her together with her wings open from a distance that I knew wasn’t disturbing her, after which I photographed a ruler in the identical spot from the identical distance and overlaid them in Photoshop. Right here’s my course of and my outcome.

Step 1: I took a photograph of a ruler towards the tree within the common spot the place the cecropia moths have been mating. I knew she was above and to the correct of the cocoon which you’ll be able to see within the pic beneath. I used the metric aspect to be a bit extra scientific about it. (Most guidebooks will provide you with moth wingspan measurements in centimeters.)

Step 2: Subsequent, utilizing Photoshop, (I subscribe to Adobe’s Artistic Cloud to make use of all their apps) I overlaid the picture of the cecropia moth together with her wings open onto the highest layer. I diminished the transparency of the moth layer to about 60% so I might see via it, after which resized it till the bark options lined up precisely with the ruler picture beneath it. That manner I knew that each layers (the ruler and the moth) have been at the very same scale. I used a gentle eraser brush to melt the perimeters and a tough eraser to exposes the perimeters of her wingtips for step 4 after I lay her over the ruler. Right here’s how that layer seems by itself after resizing.

Step 3: Then I introduced the transparency of the moth layer again as much as 100% and made certain every little thing lined up properly so I knew I scaled it correctly. At this level you’ll see the moth laid over the ruler however, except you bought actually fortunate, the moth and the ruler received’t be lined up accurately so it’s onerous to measure her precisely.

Step 4: To get an correct measurement of the cecropia moth dimension, now you’ll want to pull the moth picture over the ruler picture. I lined up her left wing tip with the 0 mm mark after which seemed the place her proper wing tip wound up.

Have you ever ever seen a Cecropia in your yard! In that case please let me know the place and when within the feedback beneath!

If you happen to loved assembly the most important moth in North America, pin it!

Hal Brindley

Brindley is an American conservation biologist, wildlife photographer, filmmaker, author, and illustrator residing in Asheville, NC. He studied black-footed cats in Namibia for his grasp’s analysis, has traveled to all seven continents, and loves native plant gardening. See extra of his work at Journey for Wildlife, Actually Wild, Our Wild Yard, & Naturalist Studio.