Horsehair Worms

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Related to Horsehair Worms: Gordian worm

Horsehair Worms


(Nematomorpha, Gordiacea), a class of invertebrates of the subphylum Nemathelminthes. The body is hairlike (the folk name is “live hair”). Coloring ranges from white to light brown and almost black. Adults are from several cm to 1.5 m in length, with a thickness of 0.5-2 mm. Adults live in fresh water or in seas (Nectonema). They lay millions of tiny eggs shaped like long milky-white cords.

The tiny nematomorph larvae parasitize in two hosts. In the body of the first (most often in the muscles of the larvae of moths, dragonflies, or mayflies) the larvae become encysted and remain there until they are swallowed by the second and final host (most frequently large arthropods). They develop to the sexually mature state in the body cavity of the second host. The full development cycle takes about 18 months. The class comprises 12 genera; six are found in the USSR, and comprise 17 species, including Chordodes longipilus and Gordius aquaticus. Horsehair worms are found as pseudoparasites in humans and domestic animals. There was formerly a folk superstition that these worms became embedded in the skin during bathing.


Kir’ianov, E. S. “Volosatiki (Nematomorpha, ili Gordiacea).” In Zhizn’ presnykh vod SSSR, vol. 2. Edited by V. I. Zhadin. Moscow-Leningrad, 1949.
References in periodicals archive ?
We found horsehair worms in the digestive tracts of two fish species at seven locations in Missouri and Minnesota:
2) Horsehair worms were found in three of five brown trout (Satmo trutta) collected by angling on 20 June 1999 in Gilmore Creek on the St.
This sample of trout was collected approximately 2 km downstream from a site where a trout that contained horsehair worms was collected in 1995 (Cochran et al.
As in the present account, many previously reported cases of predation on horsehair worms involved fishes of the families Centrarchidae and Salmonidae (Cochran et al.
Our results, along with those of McLennan and MacMillan (1984), suggest that predation on horsehair worms may occur in at least some habitats at frequencies greater than what is implied by the primarily anecdotal reports summarized by Cochran et al.
At least some of the horsehair worms we recovered from trout came from fish that were collected shortly after significant rainfall.
In Minnesota, no horsehair worms have been formally reported from Fillmore County, although Johnson et al.
Horsehair worms (Nematomorpha, Gordioidea) from Tennessee, with a review of taxonomy and distribution in the United States.
Horsehair worms (Phylum Nematomorpha) in Wisconsin, with notes on their occurrence in the Great Lakes.