Naturespeak A naturalist's view of the world

August 14, 2007

A Dangling Dagger

Filed under: Uncategorized — wykes @ 8:35 pm

  You’d think your own back yard would be safe.  Our family eats outside as much as we can in order to enjoy the late afternoon shade and talk about the day.  The last thing you’d expect to discover is that a dagger has been hanging over our heads for the last few weeks. Yes, like the very sword of Damocles itself, a large American Dagger was positioned a mere ten feet above us – a gust of wind could have sent it plummeting down upon us at any moment. Fortunately I was able to detect it before anything unfortunate happened.

  The moment of discovery occurred when I discovered a pile of grenades on our picnic table.  I knew you wouldn’t believe me, so I snapped a shot of them here for your perusal. There were dozens of them. Grenades can only mean one thing – a hairy cat is lurking about in the leaves above.  Our table is positioned under a spreading Red Maple tree. I searched the green canopy directly over the pile of ordnance for any sign of the culprit. This is what I found (see here).  It was an American Dagger Moth Caterpillar. 

  The poopertrator was revealed by it’s droppings on the table. My overly dramatic introduction to it might have been a bit misleading, but there are many elements of truth in it.  For instance, take the “Hairy Cat” part.  The Dagger Moth caterpillar is a great example of its type. The specific name for a butterfly or moth larvae comes from the old French word “catepelose” – literally “hairy she cat.”  Whether it’s a hairy he-cat or she-cat doesn’t really matter, the name got morphed into caterpillar.

  Take another look at the Dagger Caterpillar and you’ll definitely see it’s a hairy thing.  Technically only mammals (like she-cats) can have hair, so the hair-like things on caterpillars are called “setae.”  This fuzzy larvae even takes things one step further by possessing a few lashes.  You’ll note that there are several pairs of luxurious black lashes projecting out from the light yellow fur – two right behind the head, two more a few segments down and a cluster on the eighth segment just in front of the grenade launcher.

  The grenade reference is an apt description of the droppings of this cat.  In case you haven’t seen one, take a look here at a few relic World War Two shrapnel grenades. While the real devices are deadly and 4 inches long, the droppings are harmless and only ¼” long.  They consist of tightly packed leaf wastes, thus the army green shade, and the bumpy ridges result from folds in the animal’s intestines. I used to describe these as looking like those Root Beer Barrel candies, but grew tired of adding that they don’t taste the same. Now I just use the grenade analogy.

  This individual is about as big as he’s going to get – about three inches.  Soon he’ll climb down from his lofty perch, crawl under a board and weave a cocoon.  He’ll shed his fine yellow fur and lashes and incorporate them into his spinning work.  Underneath all those setae, by the way, the caterpillar is bright green. Pupation follows and a long winter rest is followed by the emergence of the adult moth next summer (it looks like this).  There is a dark dagger mark on the fore wing of the moth that lends the name to this group of night flyers.

  The “J” shaped pose exhibited in the photo is both a defensive and a resting position.  As the picture was snapped, it assumed a defensive mode because I jostled the branch (actually my son did, but that’s another story).  After taking the portrait, I let the branch swing back up into place and elected to observe the leaf muncher for a while. It resumed feeding for a few minutes before launching into a ten minute search for a fresh cluster of leaves.  Arriving at the fresh fare, the Dagger assumed this same position and I re-positioned our picnic table under it to collect more grenades (my patient wife was not as shocked by this as you might think).

  Unfortunately, the caterpillar stayed fixed in that pose for almost 8 hours, so I couldn’t gather any more “samples.”  It slept through the heat of the afternoon and didn’t become active again until 9:00 pm.  Come to think of it, this is what real cats do as well.

  There’s a real good chance you’ll see one of these insects in the coming weeks, since they feed on your common yard trees.  Keep your eye peeled for their poo and prepare to perceive this pelose ‘pillar.

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