Horsehair Worm, Scientific Name
Order Gordioida within Phylum Nematomorpha
|
Very
long, thin worms, brown to black in color. They will usually be
found in water, or, during wet weather, sometimes on the ground (as at
right). They writhe slowly and may tie themselves into knots. These worms are parasitoids, meaning they live within other animals and devour them from the inside. Animals infected include grasshoppers, crickets, cockroaches, mantids, some beetles, and even some spiders and woodlice. The adults are pretty much a bag of nerves, muscles and reproductive organs; They lack a digestive tract, any excretory system, and any circulatory system. They come in two sexes and when they mate in the water, the female will produce minute eggs which hatch to produce tiny larvae. The larvae will soon cover themselves in mucus and go into a dormant state. If the larvae are lucky they will be ingested by a suitable insect taking a drink. Once inside they bury out of the digestive tract, into the body cavity and begin to feed. Some species take over the host's brain and drive it to commit suicide by drowning. In any case, when ready they will emerge from the insect's body and seek water in which to mate. They are almost harmless to humans, but ingesting the larvae has been known to cause mild digestive upset. On the other hand, being ingested by a human or other vertebrate animal is almost certainly lethal to the larvae. There are around 320 species in the order Gordioida, infecting different insects. A scientific order is a large group; humans for example are in the order containing all mammals. A second order of horsehair worms (the Nectonematoida) is exclusively marine and is parasitic on crustacean, especially crabs. The name horsehair worm comes from the fact that cattle and horse watering troughs were prime real estate for the worms to seek mates. Imaginative folk, seeing the worms slowly writhing in the watering troughs supposed that they were horsehairs that had come to life. Their habit of tying themselves into knots led to the name of their order as well as the alternative common name, Gordian worms. In Greek legend, the son of King Gordias tied an oxcart with an elaborate knot, and an oracle then declared that anyone who could undo the knot would rule all of Asia. Many tried to untie the knot with no success. Then Alexander the Great showed up, and proved that brute force sometimes works better than careful reasoning by cutting the knot with his sword. A Gordian Knot has become a metaphor for any extremely difficult problem. |
 |