I can’t say, however, that I know of a single children’s book describing the impressive hero’s journey of Nematomorpha, commonly known as horsehair worms. From The Ugly Duckling to The Very Hungry Caterpillar to A Seed is Sleeping, these stories have brought the miracles of growth and maturation to life for generations of readers. Some horsehair worms, as they reach adult size, chemically infect the brain of their host (such as a cricket), compelling it to seek water to drink, wet, swim, and/or drown itself: the perfect environment for the adult horsehair worm.Some of my favorite children’s books describe life cycles as heroic tales of persistence and redemption. Once reaching adult size, weeks or months later, it breaks through the body of the host and starts the cycle again. There, the parasite lives inside the host, absorbing nutrients, molting as it grows. Or they can enter an intermediate host (such as the larval form of a aquatic insect) and travel with that insect as it pupates, flies over land, and dies a cricket, being an omnivore, may eat the dead “transport host,” ingesting the encysted horsehair worm that way.Īfter ingestion, the cyst “awakens” and the larval worm bores through the gut of the host and enters the body cavity. They can do this directly, with the help of barb-like hooks and knife-like stylets, or they can encyst on nearby aquatic vegetation and enter the host’s body by being eaten. Upon hatching, the rather cylindrical larvae enter their hosts (usually insects). Males die after mating females die after egg-laying.

Sometimes these are squeezed into the water in loose, small sections, like funnel cake batter sometimes they are adhered onto a stick or other surface in a compact undulating pattern sometimes they are extruded in free-floating threadlike strands. Females deposit eggs in water in long strings, sometimes up to 8 feet long, each containing up to several million eggs.

Groups of mating horsehair worms form tight knots.

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