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Horsehair worm. Scientific name: Nematomorpha. Horsehair worms are parasitic worms of the clade Nematoida alongside their sister taxa Nematoda, the roundworms. The most famous trait of certain species of horsehair worms is the ability to alter the behaviour of grasshoppers and crickets to seek water, causing the host to drown itself to complete ...
- Horsehair Or Gordian Worms
- Classification of The Animals
- The Gordian Knot Tale
- Facts About Adult Horsehair Worms
- Eggs. Larvae, and Infection of The Host
- Release of The Adult and Control of The Host
- Neurotransmitters and Behavioural Control
- Horsehair Worms and Humans
- Intriguing Animals That Are Worth Studying
- References
Horsehair worms are slender and sometimes long animals that are notable for their writhing movement. They are also known as Gordian worms after the problematic Gordian knot. They often appear to tie their body into knots as they squirm. Their larvae are parasites of arthropods, especially insects. When a larva has become an adult and is ready to le...
Horsehair worms belong to the phylum Nematomorpha. The “worms” are classified differently from garden worms, which belong to the phylum Annelida. They aren’t arthropods, either. They depend on arthropods in order to complete their life cycle, however. The phylum Arthropoda contains invertebrates with an exoskeleton (a hard covering on their outer s...
The alternate name of the horsehair worm (Gordian worm) has an interesting origin. The tale of the Gordian knot is a legend associated with Alexander the Great. According to this legend, when Alexander and his army reached Gordium, the capital of Phrygia, they encountered an ox cart tied to a pole with a complex knot. The cart had been left in plac...
There are four stages in the life cycle of a horsehair worm: the egg, the pre-parasitic larva, the parasitic larva, and the adult. The adults are found in ponds, swamps, puddles, water troughs, bird baths, human water supplies, and even toilets. They are also found on plants and in soil. Fortunately, they don't hurt people, pets, or plants. They ca...
Fertilization and Laying Eggs
Horsehair worms exist as males or females. The adults overwinter in water. In spring, mating occurs. Fertilization is internal. The male releases sperm from his cloaca into the female's body. The female later lays strings of fertilized eggs on the surface of twigs or stones in water. Each string may be one to several feet long and contain millions of eggs. The male dies after mating; the female dies after laying her eggs.
The Host of the Parasite
The life cycle from egg to adult isn't fully understood. There are believed to be several variations in the steps. Parasitizing an insect or another arthropod, such as a millipede or a centipede, is always involved. Insects are the most common hosts, especially crickets, grasshoppers, and cockroaches. The relationship between horsehair worms and insects is the best-studied one. Some species of the worms have been found in the ocean, where they parasitize crabs and shrimp.
Entering the Host
After about a month, an egg hatches into a pre-parasitic larva. This enters an insect in a variety of ways. 1. The larva may be accidentally eaten by an adult insect. In this case, it changes into its parasitic form inside the host. 2. Sometimes, the larval worm is ingested by a larval host. The worm then encysts and bides its time. It stays encysted as the host becomes an adult. If the adult is eaten by a suitable insect, the larva leaves the cyst and changes into its parasitic form in its n...
The parasite changes into an adult worm within the host's body. Adults are thought to absorb the nutrients that they need through their body surface. They obtain these nutrients from the body fluids of the host. The worm is often tightly folded to fit inside an insect, but even then, it may fill most of the animal's body cavity. Eventually, the wor...
The control of the insect is apparently mediated by an increase in the level of one or more neurotransmitters. Neurotransmitters are chemicals in animals and humans that control the passage of a nerve impulse from one neuron (nerve cell) to another. The identity of the relevant neurotransmitters in an insect host, the way in which their level is in...
Horsehair worms occasionally enter the human body when water or food contaminated by the animals is swallowed. In humans, the animals pass through the digestive tract to the anus and don't migrate into the body. They are released from the digestive tract in the feces or by vomiting. As the quote above says, they don't cause infections in humans—tha...
There is still a lot that is unknown about horsehair worms. Perhaps because they don't have a major effect on our lives, they are not as well studied as might be expected. I think they are intriguing animals that deserve more attention. This is not only because they are interesting. Studying the anatomy and physiology of other animals—even much sim...
Information about horsehair wormsfrom Oklahoma State UniversityFacts about a parasite that affectscricketsfrom Wired magazineAdult horsehair worms can be up to nearly 2 feet long and live in water. They are practically featureless, smooth, long, thin aquatic worms that writhe into knots and curls. They are not segmented like earthworms or leeches. The bodies are cylindrical in cross-section (not flattened). Both tips of the body are blunt and rounded. The “head” end (calotte) is unpigmented and only slightly set ...
Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms, hairsnakes, [1] [2] [3] or Gordian worms) are a phylum of parasitoid animals superficially similar to nematode worms in morphology, hence the name. Most species range in size from 50 to 100 millimetres (2.0 to 3.9 in), reaching 2 metres (79 in) in extreme cases, and 1 to 3 millimetres (0.039 to 0.118 in) in diameter.
Horsehair worms, also known as Gordian worms, belong to the group Nematomorpha. They are similar to nematodes but much longer (4 inches or longer) and very thin (1/80 to 1/10 inch diameter). They are found in water or wet areas, such as in or alongside streams or puddles but they can occur in cisterns, livestock watering troughs or most open ...
Horsehair worms are very long (4 to 14 inches) and very narrow in diameter (1/25 to 1/16 inch wide). Amazingly, the entire horsehair worm grew and developed as a parasite inside the body cavity of crickets and other large insects such as grasshoppers, katydids, beetles, and cockroaches. This internal parasite of insects does not harm humans ...
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They are called horsehair worms because they resemble the hairs of horses' manes or tails and are often found in areas where horses drink. It was believed as these hairs fell into water, they came to life. Adult worms mate in water and females lay long gelatinous strings of millions of eggs. Takedown request View complete answer on canr.msu.edu.
