Horsehair Worm

HORSEHAIR WORM, Gordius aquaticus (class worms-Gordiacea), up to 1 m long, resembles a horsehair tail, lives in standing or slowly flowing waters, ditches, etc. It freely swims in water, sometimes forming clusters. Eggs hatch into larvae with spines and a boring apparatus at the anterior end of the body. These Gordius aquaticus larvae bore into various aquatic insects, for example, mayflies, water beetles, and others. Further development of the larvae of W. into adult worms occurs in the second host, which can be, for example, predatory beetles that consume W.-infected insect larvae. After spending some time in the beetle's intestine, W. exits into the water where it reaches sexual maturity. The development of the North American G. robustus occurs in various insects of the grasshopper family. In popular belief, W. is falsely associated with the disease 'hair' (see Larva migrans), the true cause of which is the penetration into the epidermis of the first instar larva of the horse bot fly-Gastrophilus equi (see).