Friday, July 30, 2010
Moths are not the easiest creatures to identify. Many have similar colors and shapes with only subtle variations between species, and to make it harder there isn’t a really useful up-to-date field guide. Today’s topic, the Clymene moth, is one of the exceptions. It is very distinctive.
Name: The Clymene moth, pronounced kly-meanie, is a member of the Tiger Moth family which has over 250 species in North America. The family name is a reference to a few of the members which are boldly striped in black and yellow. Other members may be largely white or tawny; some are spotted; some are wasp mimics. The binomial for this species is Haploa clymene. There are other species in the genus Haploa but so far this is the only one I have seen.
When and where seen: Ellen Huber took the photo of this Clymene on July 21. The moth was on the front door of the Sleeper room where it had already been for several hours when it was pointed out to Ellen. It is active both day and night and is known to come to lights. It also visits flowers. I have seen them other years, early in August, near the Poole swamp on School Street and in the Towle woods. The caterpillars feed on plants in the aster and borage families and other rich sources of pyrrolizidine alkaloids. They are quite fond of Eupatorium (a genus that includes Joe-pye weed). There are large stands of it at the Cranberry Bog. Later in the year, and again next year up through June, this would be a good place to look for Clymene caterpillars. You can find them quite early in the year because they spend the winter in their caterpillar form.
Identifying characteristics: The Clymene moth has a delta-wing shape when at rest. They are usually around an inch long. The forewings are off-white with very dark brown markings that form a bilaterally symmetrical fleur-de-lis pattern down the center back – typical of bold markings designed to strike fear in the heart of predators. (What immortal hand or eye, could frame that fearful symmetry?) The hind wings, not visible when the moth is at rest, are pale orange. The caterpillar is black with broken yellow stripes along its sides. Like many tiger moth caterpillars it is hairy. The best known caterpillar in the tiger moth family is the Woolly Bear. The Clymene caterpillar has clusters of yellow-brown hairs all over but not as densely packed as on the Woolly Bear.
Tiger moth tangent: I first learned of tiger moths in their other manifestation – as bi-wing aeroplanes. My first encounter was with one being used as a crop-duster in the south of New Zealand. I also remember being entertained as a child by our local daredevil stunt pilot flying his tiger moth in loop-the-loops, apparently attempting to emulate the flight pattern of its namesake.
Department of Defense: The caterpillar and the adult Clymene each have more than just a single method to opt out of their role as prey in the food chain. Many predators find the hairs on the caterpillars to be a deterrent while others have learned that the caterpillar tastes bad (if not toxic) due to the alkaloids it accumulates from the plants it eats. The adult moth, like other tiger moths, uses its bold markings as a kind of warning system, which is well and good until you consider animals that don’t hunt by sight. Bats. To combat a bat takes a little more ingenuity. Tiger moths, like owlet moths, have a tympanic organ that can pick up a bat’s sonar system giving them time to take cover. The tigers have taken things a step further than their owlet cousins and developed a way to generate a clicking sound. This has the effect of totally changing the bat’s mind about what’s for dinner. The click is either interpreted as a poison warning or it interferes with the bat’s sonar. Either way, the tiger is safe.
Sources: Kaufman Field Guide to Insects of North America, Eric R. Eaton, Ken Kaufman; Insects: Their Natural History and Diversity, Stephen A. Marshall; Discovering Moths, Nighttime Jewels in Your Own Backyard, John Himmelman; Caterpillars of Easter North America, David L. Wagner.
Submissions: Please feel free to claim this space and write the Biodiversity Corner on any species that occurs in the wild and you have found in Carlisle. ∆
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