SON OF POSEIDON EMERGES IN MY OFFICE   

Thursday, June 16, 2011

There was a big moth with a five inch wing span fluttering around my office one day last week.
 
Perhaps I should start at the beginning. Got an e-mail from Picton Farm Supply. Staff employee Wendy Townsend said that someone had brought in a cocoon, and would I be able to come in one day and have a look at it? About a week later, I finally made it in and announced that I was pretty sure that it was the cocoon of a Polyphemus moth, but could I take it home with me to verify? The cocoon was taken and put in the back of the car where it rode around for most of the day before I remembered to bring it in the house where I was able to identify it as belonging to a Polyphemus moth.
 
I left it on my desk, and later placed it atop a fluorescent light fixture above my desk where it sat for a few more days, intending to add the new acquisition to my box of props that I take along on guided hikes. Figured it would be useful on one of those hikes where few things show up and an emergency item is required to add some interest to the hike. 
 
Last week I entered my office to do some work and met a large Polyphemus moth fluttering in front of my eyes which then landed on the light fixture. Sure enough, the abandoned cocoon that I had placed on the light fixture, had a small opening at the one end, where this creature had emerged, unfolded his wings and dried off. I carried him outside and placed him on the sun deck railing so he could get on with what`s left of his life – roughly two weeks. Hardly worthwhile to come out of the cocoon. What amazed me was the size of this moth and that he had somehow been compacted and folded enough to fit in this cocoon that was barely an inch in width and a little more than an inch in length. The sundeck railing is five inches in width, and his wings extended beyond either edge.
 
So, what’s with the unusual name? Well, Polyphemus was actually the mythological gigantic one-eyed son of Poseidon and Thoosa in Greek mythology, one of the Cyclopes, mentioned in The Odyssey of Homer. The moth itself is actually fairly common and, superficially, resembles the more familiar cecropia moth somewhat in that it has the two large eyespots on its hindwings, which give the Polyphemus its name. Eyespots also serve as startle patterns, a form of distraction should a predator come along. Even its light colouration serves as a camouflage to some degree, despite the moth’s huge size.
 
This is not the only animal that uses these startle tactics. Most startle patterns are brightly colored areas on the outer body of already camouflaged animals. A good example of the use of startle patterns is the gray tree frog. If you find one, and it is difficult as they change colour to match their background, check its leggings. They are bright yellow. When it leaps, a flash of bright yellow appears on its hindlegs, usually startling any predator away from its prey. In the case of the Polyphemus and the cecropia moths, the false “eyes” are believed to be a form of mimicry, meant to misdirect predators. The predator thinks it is meeting its prey head on, only to see it successfully flutter away in the opposite direction.
 
Insects have evolved numerous ways to ensure survival. So expertly do some match their background, it is often difficult to spot them, even after the location of an individual has been pointed out. Others are transparent allowing the background to filter through so there is no need for the insect to seek out habitat that resembles itself. Any old place will do. Others like the Monarch butterfly, contain cardenolides, a toxin that it obtains from milkweed plants, and carries with it through the larval stage and into the adult stage. Birds and other predators soon learn to avoid Monarchs. The very similar viceroy butterfly is not in the least bit poisonous, but uses its resemblance to the Monarch butterfly as a defence.  The newly arrived giant swallowtail butterfly – even larger than my Polyphemus moth – as a larva, has a defence that is guaranteed to thwart the efforts of any predator. First, it resembles a large bird dropping which is usually sufficient to turn off most birds from pecking at it. And, if that doesn’t work, it uses chemical warfare, producing a foul odour from its tiny body that permeates the air around it. Fascinating stuff when you really get into it.
 
My moth is more than likely dead by now, having lived out its short lifespan, but not before finding a female (mine was a male, obvious by the feathered antenna) which will lay its eggs singly, and seemingly at random, on the lower surface of leaves. Although the larva feeds voraciously on leaves, it does not feed with thousands of others of its own species like the forest tent caterpillars do that we saw along Moneymore Road near Marlbank last year at this time. The Polyphemus is common enough, but certainly not invasive.  It tends to scatter eggs here and there, rather than concentrate them in masses on individual leaves; consequently, the number of caterpillars on any one tree is usually low. It feeds in solitude, and then, constructs its characteristic cocoon wrapped in leaves on the tree. Here, it overwinters as a pupa in its large, thick, tough, silken cocoon.
 
In late May or early June, the moth emerges from its cocoon where it spent the winter and commences its short life in the wild – or, in the case of the moth I had   – in the office of our home, after being unceremoniously jostled about, likely many miles from where it had spun its cocoon, confident that it would not be disturbed.