Gordius difficilis was found at three locations in Allamakee, Winneshiek, and Fayette counties. difficilis was known from several cold spring-fed habitats in southeastern Minnesota, surveys targeting this species were conducted in similar habitats in northeastern Iowa. Abstract: Two species of horsehair worms (Chordodes morgani and Paragordius varius) have been reported previously from Iowa or its bordering waters, and two species (Gordius difficilis and G.The common name of the phylum Nematomorpha is horsehair worms, and is used here for convenience. Inside there is a ventral cord containing nerve tracks but no similar dorsal cord. There is a vent (cloaca) at the rear end of the body but there is no mouth. It does not have lateral rows of hairs (setae), but it does have bristles that aid in swimming.

The outer layer often has groups of wart-like or pimple-like bumps (areoles). The body is unsegmented and is covered by a thick, two-layered cuticle. There is a blunt head and a swollen tail, but there are otherwise no distinguishing features that can be seen in the field without magnification.

The body color is purplish-brown to black in most species, tan in some species. They are 1⁄ 32 ″to ⅛ ″ (1 to 3 mm) in diameter and are usually 12 ″ to 16 ″ (30 to 40 cm) long but some can grow up to 47 ″ (120 cm) in length. They do not feed, but may absorb nutrients through their body walls.Īdults are very long, hair-like worms. They are found usually in freshwater habitats, sometimes in semi-aquatic habitats, or inside terrestrial hosts usually near water. It is thought that they influence the behavior of their host, bringing them near water when the adult is ready to emerge.Īdults are free-living. They feed on and absorb nutrients from the gut of their host.

Larvae are parasites of insects, mostly grasshoppers, crickets, and katydids (Orthoptera). There are about 320 (Wikipedia) or 356 (Encyclopedia of Life) species in 18 genera in 2 families worldwide, at least four species in North America north of Mexico, and at least 2 species in Minnesota. It is the only order in the class Gordioida. Gordioidea is an order of parasitic horsehair worms.

Download horsehair worm