Asp

Known around these parts of Southeast Texas as an “asp”, the caterpillar of the Southern flannel moth (Megalopyge opercularis) hides poisonous spines within the pelt of hairs that cover it.  Labeled as the most venomous caterpillar in the US, this harmless looking caterpillar has a sting from that packs a wallop, which I have experienced personally. If I were to try and describe its severity- it's akin to placing the business end of a lit cigarette against your skin.  I’ve read that a good way to ease the pain is to remove any spines that were left behind in your skin with a piece of cellophane tape.

Chrysalis vs. Chalcid Wasp

Back on August 17th my granddaughter and I were out in the front yard trying to get a photograph of a hummingbird that was feeding on some turk's caps.  All of a sudden I hear her cry out "paw paw look!"  I turn to see the chrysalis of a spicebush butterfly attached to a metal birdhouse we have hanging in one of our flower gardens under a camphor tree which, by the way, is one of this butterfly's  host plants.  I had been standing right next to it and  never noticed.  I'm constantly amazed how she has become adapted at observing things, most times before I do.

We decided to keep an eye on it day to day to see if we might be lucky enough to be around when the butterfly emerged.  That was to never be.  What I should have done was placed it in a jar protecting it from its natural enemies.

Today we found that it had a tiny hole in it.  And when I saw this I knew it meant trouble.  This is the workings of a chalcid wasp.  These tiny wasps lay eggs into the chrysalis during the time that it is formed when the tissue is soft.  The eggs hatch and the resulting larva consume the insides of the chrysalis and eventually develop into wasps which then bore a hole, as seen above, to escape.

Note in the first photo how the back end of the chrysalis is relatively straight.  In the second photo it is bent.   This is one of the signs of chalcid infestation.  Once the eggs of the wasp develops inside and begins to consume the developing butterfly within, the chrysalis dies and the muscles that once held it straight relax causing the bend to form. 

Check out this cool video showing how this wasp develops:


References and Suggested Reading:

1) Spicebush Butterfly Post
2) Chalcid Wasp Links  (a), (b)
3) Caterpillars of Eastern North America