I finally collected them all!

Spun Glass Slug Moth (Isochaetes beutenmuelleri). This animal is likely not in its last instar and should have even larger arms before its ultimate diapause.

Maybe I owe those of generation Y and the Millennials a bit of a silent apology. I too have been on a mission to ‘collecting them all.’ In my case, however, I think the objects of my search are far more brilliant, fascinating and mysterious than anything in the Pokemon universe could ever dream of being. For about the past four years, I have been occupied in late August to late September with finding all the slug moth caterpillars that can be found, or at least expected, in the state of Missouri.

Spun Glass Slug Moth (Isochaetes beutenmuelleri). This species, like most of the limacodids, are generalist feeders. The slug moths can be found on virtually any species of woody plant in Missouri.

Many thanks to Kyran Leeker for pointing me to a couple of hot spots she had found that contained some of the last species of slug moth caterpillar I needed to find and photograph – the spun glass slug moth, or Beutenmueller’s slug moth (Isochaetes beutenmuelleri). After hearing this, Sarah and I hit these locations soon after. My radar for these creatures was definitely in need of a re-calibration. I did not find a single slug moth caterpillar but Sarah found three, including this I. beutenmuelleri and two smaller parasa (Parasa chloris) – a species I had found before, but only had photographed with my cell phone. This was an exciting day indeed!

Spun Glass Slug Moth (Isochaetes beutenmuelleri). Sometime during late September to mid-October this little one will spin a cocoon and overwinter. In the spring it will then pupate into a non-feeding adult moth.

Although not as colorful or spiny as some of its more flamboyant relatives, the smaller parasa (Parasa chloris) is quite an interesting slug moth in its own right. Individuals can vary a lot in their patterns and are warmly toned with tans, oranges and pinks. I can’t get enough of looking at these guys.

Smaller parasa (Parasa chloris). Each of its humps is equipped with a few barbs that can inject an annoying, but not dangerous venom.
Smaller parasa (Parasa chloris) with wood grain or marble-like pattern.
Smaller parasa (Parasa chloris) with its head out of its protective hood.

Sarah found the following poor creature. Although you can’t help but feel sorry for it, I was glad to capture this natural history story. This little one was gregariously parasitized by approximately 15 braconid wasps, likely from the Microgastrinae subfamily.

Smaller parasa (Parasa chloris) parasitized by braconid wasps. Note the multiple stages of wasp development, from larvae that have completed their cocoons, to those still at work spinning their webs to larvae just emerging from their host. Their is no chance for the survival of this caterpillar.

These wasps were definitely in the process of preparing for their next stage of life. I have come across lots of caterpillars in the past that were parasitized by wasps like this, but always after the larvae had emerged and spun their cocoons  and often after the wasps had cut the tops off and exited. This was very special indeed, finding them in this process. This was taking place much quicker than I had anticipated. It was plain to see the movement of the wasps and observe their progress. I had to take some video to capture this. I have sped the footage up by 1.5X to better showcase this activity.

Before I finish, I couldn’t help but think of one of my favorite Darwin quotes. Watching this footage a few times, I couldn’t help but agree with his reasoning.

In a letter to his friend and botanist, Asa Gray, Darwin wrote…

With respect to the theological view of the question: This is always painful to me. I am bewildered. I had no intention to write atheistically, but I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars …”
-Charles Darwin

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