Prince Edward County, Ontario, Canada
GIRL OF LIMBERLOST AND SON OF POSEIDON November/December, 2013 issue The photo of the caterpillar that Scoop editor Angela Saxe sent me, taken by Isadora Spielmann, was a mystery. Covered in tiny white spiracles, the caterpillar’s identity was lost in the carpet of these white protuberances. So, I sent the photo to friend Joe Bartok in Tweed who seldom has been stumped by other mysteries I have e-mailed him in the past. Pretty sure that this was an Imperial Moth, he was however curious about the white bumps, whether they were natural or parasites. He forwarded the photo to a website called BugGuide, and inquired about the white spiracles. They replied, “The white bumps you refer to could either be the scoli (fancy word for spines) or the spiracles, both normal features. This caterpillar looks healthy but could still be parasitized.” Moreover, the caterpillar was identified as Eacles imperialis pini, an Imperial moth species that feeds specifically on pine. What was amazing, attributable primarily to the speed of the Internet and electronic messages, it took only the better part of a day to pin an identity on this creature. Naturalist Gene Stratton Porter's “A Girl of the Limberlost” features E. imperialis prominently in the plot development. Butterflies and moths are fascinating, but in the larva or cocoon stage, their identity can be a little challenging. Two years ago, I walked into my home office to find a huge moth fluttering in front of my face. Earlier I had received an e-mail from a Picton farm supply staff member about a strange cocoon someone had brought into their store. The store sold bird feeders, so surely they must know the identity of a cocoon! It spent several days jostled about on a shelf between farm catalogues and order forms. I was quite certain that the object that I now rolled around in my fingers was the cocoon of a Polyphemus moth, but I would need to take it home with me to verify. The cocoon was placed in the back seat of the car where it rode around for three days before I remembered to bring it into the house where I was able to verify it as a Polyphemus moth. I left it in my office, and later placed it atop a fluorescent light fixture above my desk where it sat for a few more days. I intended 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 interest to the hike. That’s when 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 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 coming 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 two large eyespots on its hind wings, 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 hind legs, 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 recently arrived giant swallowtail butterfly six years ago – 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. My moth likely lasted only a few days, 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 invaded one section of forest along Moneymore Road near Marlbank three years ago. 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. Meanwhile, if you get a chance, check out Joe Bartok’s website blog, “Tangled Web” . Contained in it is some really fascinating information about plants and insects that many of us simply overlook in our travels. I think his quote from naturalist Louis Agassiz, says it all, “I spent the summer travelling; I got half way across my backyard.” For more information on birding and nature and guided hikes, check out the NatureStuff website at www.naturestuff.net Terry Sprague lives in Prince Edward County and is self-employed as a professional interpretive naturalist.