Thanks to the sharp eyes of Erik 'The Caterpillar Hunter' Draper (OSU Extension, Geauga County), this very rare caterpillar made an appearance at yesterday's 83rd Ohio Plant Diagnostic Workshop. The Paddle Caterpillar is the larval form of the Funerary Dagger Moth (Acronicta funeralis, family Noctuidae).
The common name for the caterpillar comes from the odd, paddle-shaped hairs (setae) that extend from the sides of the caterpillars. The effect makes the caterpillars look a bit like a trireme; the ancient Greek and Roman war galleys. In his book, Caterpillars of Eastern North America (2005, Princeton University Press), David L. Wagner leads off his description of the caterpillar by calling it, "a flamboyant dagger" referring both to the setae as well as the bright yellowish markings on top off each body segment.
Dagger moths are so-named for their distinctive black dagger-shaped markings on their forewings. The "funerary" in the common name of this moth comes from their black and gray coloration which reminded some entomologists of funeral clothing. Of course, you may need a flashlight or porchlight to see the adults since they are night fliers as indicated by the family name, Noctuidae.
Erik came across the elusive caterpillars on oak while he was collecting diagnostic samples in the OSU OARDC Secrest Arboretum for the Workshop. However, the caterpillars will also feed on the leaves of a wide range of trees and shrubs including: alder, apple, birch, blueberry and huckleberry, cottonwood, dogwood, elm, hazelnut, hickory, maple, and willow.
Although the moths have a relatively wide geographical range including all of Ohio, the rarity of Erik's caterpillar find is illustrated by Wagner's statement at the end of his description of the caterpillar: "Unfortunately, this spectacular insect is rather scarce - I've never found its larva." Indeed, in the Ohio Division Wildlife's Moths of Ohio Field Guide, the dagger moth entry ends with, "… the Paddle Caterpillar (Acronicta funeralis) is armed with bizarre filaments tipped with spoon-shaped paddles. It is a holy grail for caterpillar seekers."