Spiny Oak Slug (Euclea delphinii)
Saturday, August 27, 2011
Mount Vernon (Map 20)
I was picking up some scrap lumber stacked by a large spruce tree in our back yard and found a strange small caterpillar underneath one of the boards. Brightly colored with green, red, yellow, and orange, measuring only about 2 1/2 cm in length, it bore an array of fleshy protrusions and horns bristling with fine spines. In stark contrast with its colorful upper body, its underside was a milky translucent white with rows of shallow polyps instead of any noticeable feet.
I took some photographs and then went online to see if I could find a match. A quick search turned up some nearly identical images, identified as a “Spiny Oak Slug” caterpillar, Euclea delphinii. Numerous entries state that this moth larvae feeds on the leaves of oak, maple, and apple trees (all nearby to this caterpillar where found) as well as other deciduous trees and broad-leaved woody plants, with Maine and Quebec its northern range. Colorful for a reason, this is one of a group of “stinging caterpillars” with venomous spines. Just as well that I didn’t touch the caterpillar then, though that might have verified the identification. The Spiny Oak Slug can exhibit a great deal of variation in coloration and markings. This particular caterpillar was definitely one of the most bizarre-looking bugs I’ve seen in Maine. HJM
