Today at The Caterpillar Lab Orgyia tussock caterpillars hatched and wandered across the tattered remains of their own mother's life cycle - her final shed caterpillar head capsule, a piece of her discarded pupal skin, and mats of her silk and severed defensive hairs. She left behind this evidence of her life as an offer of protection to this next generation. Below, an old essay describing the Orgyia's unique life cycle.
For some species, it starts and ends with the caterpillar:
We have been trained to think of cycles of growth and reproduction with a definite starting place and a definite end. Perhaps that is why caterpillars have historically received so little attention. They are the middle, the filler, the teenage years that will fade into obscurity. A close look into the natural history of the larva could never illuminate upon the overall nature of a creature. Could it?
I have been trained to think of my own life in this way as well. Always working towards some future stable point, when I am finally complete with wings and functioning gonads. Hold my breath, close my eyes, and maybe, if I am lucky, I will come out the other side of this, free of parasitoids and structural defects. Then I can be rebuilt into the stable adult form.
What a waste of good life, of rare and valuable time on this planet; to be thinking this way. We teach metamorphosis in the classroom and we draw parallels to our students development. It is a horrible message indeed, if we deny the beautiful sovereignty of the caterpillar. And we as naturalists risk missing so much wonder, and so many secrets, if we make a practice of always reducing the immature stages of life to a marginalized "in-between".
For the genus Orgyia, it really is all about the caterpillar. The caterpillars are adorned with a wide variety of setae, from venom-covered spikes, to barbed chimneys, to long dense brushes. Acting together the hairs ensure that the caterpillar is well defended against both bird and insect predator. But the caterpillar is not selfish, it shares its valuable defenses with later incarnations of itself. Plucking itself naked, it weaves the defensive hairs into its cocoon to help protect the immobile pupa. Further, the wingless adult female may gain some protection from these hairs, as she never leaves the cocoon's surface as she breeds, lays eggs and eventually dies. The eggs certainly gain some advantage plastered in a clump amongst the previous generation's larval spines. And when the caterpillars hatch, the tiny first instars will rest a while on the protected cocoon before ballooning off into the world in search of food.
A caterpillar, a lowly larva, something that we often overlook when trying to describe a species, is providing the protection for every other stage in the insects life cycle. How often do caterpillars play such a significant role? Perhaps it is time to reevaluate this in-between creature.