The young larvae creep along the bottom of their watery homes, seeking passage to the body of a cricket, grasshopper or beetle. As waters warm in spring, the female worm sheds as many as 27 million eggs into the water, many of which are fertilized by the male as he passes over them.
Upon emerging from its host the horsehair worm spends time in or near its body of water, eventually finding a relatively warm place to spend the winter. A single horsehair worm displays its characteristic tangle. Does it control its host zombie-style, depriving it of its own grasshopper consciousness? Perhaps-and the image is strangely disturbing. Somehow it must induce thirst in the grasshopper, driving it to approach water to drink. One question about the worm is unanswered: how do the parasites know when the insect is close to water? If it emerges in a dry hot place, it will surely shrivel in the sun. Upon examination fully one grasshopper out of twenty harbored the tightly coiled worm, a death sentence for it as sure as the dissecting scissors that exposed its fellow traveler. One summer long ago I participated in an informal survey of the grasshopper population to determine the rate of infection. Horsehair worms are common parasites of those insects.
In fact, it is associated not with horses at all, but with beetles, crickets, and grasshoppers. For this reason-it takes on a more horsey hue–it is given another name, horsehair worm, perhaps in the mistaken belief that it originates from horses come to drink at watering troughs. It may be iridescent white if it has recently appeared, but rapidly turns a dark brown as time passes. Perhaps not as intricate as the real Gordian knot, the Gordian worm nevertheless displays a formidable tangle, its length sometimes stretching to 36 inches or more. Horsehair worms are harmless to humans… but not crickets. After a few futile attempts he simply took out his sword and whacked it in two, presumably showing his contempt for that story. As some readers may remember from school, Alexander the Great was confronted with the Gordian knot, having been told whoever untied it would rule the known world.
In late summer in puddles, bird baths, pools, and even wet grass a long, thin writhing worm can sometimes be found, often coiling in extravagant knots, that behavior explaining one of its names, the gordian worm.
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