The rains have brought all kinds of strangeness to the woods. As we wrapped up our surveys of stream salamanders, a cry went up: nematomorph! (Yes, this is an advanced class; in Introductory Biology the cry would have been, OMG-gross…) Lying on the stream bed was half of a Narceus millipede with a long white worm writhing its way out of the broken body. The millipede’s front legs were still grasping feebly at the ground. It had dragged itself several feet to this spot, leaving its other half discarded on the wet rocks.
This individual was not alone. Barely ten minutes later we found another, this time with both halves still encasing the emerging parasite.
I’m fairly confident that the students’ identification of the cause of this distress was correct: a nematomorph worm emerging from its host. However, the light color of the worm makes me a little suspicious that a mermithid nematode might also be the culprit. My search of the scientific literature revealed nothing about either of these worms in this particular host, so we may have stumbled into new corner of the vast wonderland of pain that is animal parasitism. We’ll likely head back down into Shakerag Hollow to see if we can find more worms to bring back to the lab.
Nematomorphs appear in the first chapter of The Forest Unseen as examples of one extreme of the continuum between cooperation and conflict. The worms eat their hosts from the inside out, with no regard for the comfort of the suffering victim. The vital organs are left in place to allow the host to continue feeding (the food goes mostly to the inner pirate, of course). At last the parasite directs its hollowed-out victim to water. There the worm breaks free, discards its dying carrier and squirms away to look for a mate.
After one of my recent public lectures, someone recently asked me for an example of what I meant by the “weight of the world’s pain” (what a blessed life the questioner must have led). This species could surely serve as an answer.
Some visceral fears are tapped when we observe the emergence from within of a life-robbing villain. I think these fears may, in part, be rooted in our species’ long history with parasites, some of which do indeed emerge through our flesh, others merely use existing exit orifices. Either way, we recoil in horror. Movie-makers titillate these deep-seated fears when they show slick-bodied monsters sliding out of our skin. And Freud et al‘s ideas of the unconscious are so successful because of our pre-existing and, ahem, unconscious fear of what might be hidden within us (oh delicious infolding circularity). Psychoanalysis entices because it promises to draw out the appalling inner worm, a cleansing that is surely the deep desire of all animals.
OMG — FANTASTIC!
I think it depends somewhat on which side you’re on. I love to see parasitized hornworms on my tomatoes. I leave them to their suffering for the greater good.
Hornworm parasitoid wasps definitely take their toll and thereby yield more tomatoes. But pain is still pain, even if it gives life to some other species. The cold calculus of life’s rules: we live by consuming and trampling on others.
This is one of my favorites.
Splendid, that Captain Higgins story.