Saturday, January 28, 2012

Cecropia cocoon



On a recent foray in search of winter birds, I found myself crashing through a dense thicket of gray dogwood, various well-thorned Rubus blackberries, and sundry other saplings and shrubs. I didn't produce any exciting avifauna during my brush wading, but the effort was time well spent. At one point I paused to look and listen, and there, nearly in front of my face, was the cocoon of a cecropia moth!

The cecropia, Hyalophora cecropia, is one of our silkmoths and every aspect of their life cycle is of great interest. Excepting the eggs, their cocoons are the least conspicuous phase of this moth's four-part life cycle. It's a hefty cocoon, but looks just like a leaf that has fallen and draped itself over a twig.

I was sorely tempted to carefully open it to photo-document the pupa within, but decided against it. Better to leave well enough alone and not hinder the stunning transformation that will take place this spring. Although the cocoon looks like nothing more than a dead leaf, its contents are very much alive albeit in a state of suspension for the winter. However, Nina of Nature Remains did successfully reveal the contents of a cecropia cocoon, photo-document the whole thing, and put it back together and eventually hatched the moth. See that spread HERE.

Photo: Shawn Hanrahan, Wiki Commons 

Few people notice the eggs of the cecropia, which are laid on one of the myriad woody plants that serve as host plants. The eggs aren't there long - in short order tiny first instar caterpillars will hatch.

Photo: Michael Hodge, Wiki Commons

By the time the caterpillars have molted into their fifth and final instar, they have become behemoths adorned with spiky clubs. A mature cecropia cat is an eating machine, and stuffs itself with foliage to prepare for the long winter's siesta in its cocoon.

 Photo: Tom Peterson, Wiki Commons

Finally, if all goes well and none of the moth's numerous predators takes it out at some early stage, a gorgeous moth will emerge. The cecropia is the largest moth species that commonly occurs in North America and an adult is an unforgettable sight. Last year seemed to be a good year for cecropias in Ohio, and I fielded several queries about them from people who had never seen one. In every case, these cecropia newbies were floored by the size of the moth, and typically described them as the size of a bird or bat. Big females can have a wing spread that spans over 6 inches!

Silkmoths have no functional mouthparts, and live only to mate and produce eggs. Thus, the ultimate phase of this complex life cycle, the moth, lives for only a week or so.


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3 comments:

Katie (Nature ID) said...

I have been very impressed with your blog, even though I don't comment much. Your blog makes me ache for the natural beauty that is Ohio. Thank you for sharing your finds and knowledge. Say "Hi!" to Dr. Horn at OSU for me.

Terry K.Andrews said...

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Katie (Nature ID) said...

Ugh. These spammers are starting to get under my skin and irritate me in the blogosphere. They seem to be getting better at their craft, too. I will continue to enjoy your blog. Thank you for sharing your cool finds and information. Again, say "hi" to Dave if you get the chance.