This picture clearly captures the creature in question. We see that it is very long (probably at least 9 inches), white, and thin. We believe this is a horsehair worm! While mature horsehair worms are darker in color, they are white when they first emerge from their hosts (this will be explained in the next paragraph). Also, horsehair worms live in water, so our reader finding the creature in a spring box is a helpful clue.
Horsehair worms are threadlike worms, named because they resemble the hair of a horse’s tail or mane. They are very thin, and usually between 4 and 14 inches long. Horsehair worms develop as parasites in the bodies of crickets, cockroaches, beetles, and some grasshoppers. When they are mature and ready to lay eggs they wait for their host to go near a body of water and then eject themselves from the host’s body. Host insects die as a result of this process. However, horsehair worms are harmless to humans and pets.
In summary, a reader found a thin white worm in her spring box. Although we aren’t sure how this horsehair worm ended up in our reader’s spring box, we aren’t very surprised. It is relatively common to find horsehair worms in ponds, water cisterns, water troughs, and swimming pools. Since our reader also discovered 2 salamanders, perhaps the box isn’t properly set up.
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