Common But Commonly Overlooked: Horsehair Worms

The FB post a few days ago about the Siberian worms (nematodes) that revived after 30k years in permafrost made me remember, back in my teaching days, of seeing similar-looking horsehair worms (or having students bring them in for extra credit).

They were rather common around farms and wet margins of yards. Often they’d be found in a tight ball resembling the mythical Gordion Knot, giving them one of their common names.

You can see how they move in this video:

 They are not nematodes, but superficially resemble them and are in their own Phylum, Nematomorpha. There are some 300 species; some grow to more than six feet long–far in excess of the length of their host grasshopper et cetera.

They are very simple creatures but can have complex life cycles—including the zombie effect of making a host beetle or grasshopper commit suicide by jumping into water, since this is necessary to complete the worm’s life cycle.

And no, they do no harm to humans—except weird them out. It is freaking to hold one of these in your hands—like a stiff animated strand of the world’s strangest pasta noodle.

If you have seen these before, please tell me if it was recently and in what kind of habitat. Did you identify the host that filled the role that you see in this video of three large worms emerging from an unfortunate praying mantis?

Author: fred

Fred First holds masters degrees in Vertebrate Zoology and physical therapy, and has been a biology teacher and physical therapist by profession. He moved to southwest Virginia in 1975 and to Floyd County in 1997. He maintains a daily photo-blog, broadcasts essays on the Roanoke NPR station, and contributes regular columns for the Floyd Press and Roanoke's Star Sentinel. His two non-fiction books, Slow Road Home and his recent What We Hold in Our Hands, celebrate the riches that we possess in our families and communities, our natural bounty, social capital and Appalachian cultures old and new. He has served on the Jacksonville Center Board of Directors and is newly active in the Sustain Floyd organization. He lives in northeastern Floyd County on the headwaters of the Roanoke River.

2 thoughts on “Common But Commonly Overlooked: Horsehair Worms”

  1. Well Fred i saw this on a cricket in a swamp where i was looking for fish bait i new there were parasites in some of them but it was this kind of worm thanks for telling us about them

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