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What species is this worm?

What species is this worm?


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I was at the park lying on the grass and its the third time I have seen them, I used to think they were parasites when I was like 7. It is the very small brown worm on the green leaf. It moves by squiggling. It comes in different colors but same size.

http://postimg.org/image/ea3x2nw95/ http://postimg.org/image/zfawh9pr1/


For me it looks like an inchworms which are the larvae of geometer moth or Geometridae.

By your picture it is almost impossible to see of which type it is.

I took picture of one in Switzerland (but likely not the same as yours).

Full resolution here: https://flic.kr/p/utFsiU


Is this what you mean?

It's pretty hard to tell from this photo, and I'm no entemologist, but to me, it looks like it may be a wireworm, a larvae of a click beetle. This is a diverse group, so I think it would be pretty difficult to give a specific identification. (More images)


New Species of Microscopic Worm Has Three Sexes, Lives in Arsenic-Rich Lake

An international team of biologists has isolated eight species of nematodes from the arsenic-rich sediments of Mono Lake in the Eastern Sierras of California. One species, temporarily dubbed Auanema sp., is new to science, culturable, has three different sexes, carries its young inside its body like a kangaroo, and can survive 500 times the human lethal dose of arsenic.

Auanema sp. lives in the high-salt, high-pH, arsenic-rich Mono Lake. Image credit: Shih et al, doi: 10.1016/j.cub.2019.08.024.

Mono Lake is three times as salty as the ocean and has an alkaline pH of 10. Before this new study, only two other animal species were known to live in the lake: brine shrimp and diving flies.

In the new work, Caltech Professor Paul Sternberg, University of Haifa’s Dr. Amir Sapir and their colleagues from the United States, Japan, the United Kingdom and Israel found eight more animal species, all belonging to a class of worms called nematodes. Only three of them are known to science.

All eight species are diverse, ranging from microbe-grazers to parasites and predators. Importantly, all are resilient to the arsenic-laden conditions in the lake and are thus considered extremophiles.

“Extremophiles can teach us so much about innovative strategies for dealing with stress,” said Caltech Dr. Pei-Yin Shih, first author of the study.

“Our study shows we still have much to learn about how these 1,000-celled animals have mastered survival in extreme environments.”

One of the new species, Auanema sp., exists in three different sexes: hermaphrodites, females, and males.

The hermaphrodites can produce offspring by themselves, but the females and males need to mate in order to produce their young. The females and males are often produced early in the reproductive cycle of the mother, followed by the hermaphrodites.

“One potential explanation for this three-sex life cycle in Auanema sp. is that the females and males could help maintain genetic diversity through sexual recombination, while the hermaphrodites could disperse into new environments and establish new populations there — since they can grow a population by themselves,” said Caltech Dr. James Siho Lee, co-author of the study.

When comparing Auanema sp. to sister species in the same genus, the researchers found that the similar species also demonstrated high arsenic resistance, even though they do not live in environments with high arsenic levels.

In another surprising discovery, Auanema sp. itself was found to be able to thrive in the laboratory under normal, non-extreme conditions. Only a few known extremophiles in the world can be studied in a laboratory setting.

“Our findings expand Mono Lake’s ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance,” the scientists said.

“The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles.”


Characteristics of the Common Earthworm

The common earthworm (Lumbricus terrestris) resembles a cylindrical tube, with an average length of about 7 cm. – 8 cm., with some members of this species even growing to 35 cm. They are found abundantly in North America, Europe and western Asia.

The reddish-gray colored body of the earthworm is segmented, and the vital organs are present in particular segments. The skin is covered by a moist mucous layer that serves the main purpose of respiration (exchange of air). An earthworm does not have any locomotory organs and therefore moves by means of muscle contraction and relaxation.

The earthworms are also known as night crawlers because they are usually come above ground during the night. During the day, they burrow the ground using their strong toothless yet muscular mouths. While burrowing, an earthworm feeds on dead plant materials and organic matter present in the soil. The ingested food is broken down into finer particles in its muscular stomach also known as gizzard. The fine food particles are acted upon by various enzymes for digestion process. Useful nutrients are absorbed and undigested soil and other particles are passed out as worm casts. Studies have revealed the presence of useful soil microorganisms in earthworm casts.

The earthworms also transfer nutrients and minerals from the earthen layers below, to the surface above through their waste. The small burrows that they create keeps the soil aerated. Thus the earthworms play a vital in maintaining the health of the soil.

Earthworms are hermaphrodite, meaning both male and female sex organs are present in the same body. However, reproduction takes place via cross-fertilization. The eggs are enclosed in an egg casing or a cocoon. The juvenile earthworm resembles an adult worm, except that it lacks sex organs. It attains sexual maturity within 2 – 3 months after hatching.

One of the characteristic features of many different species of earthworms is their ability to regenerate lost segments of their bodies. The lifespan of the earthworm varies depending upon the species the common earthworm can live up to 6 years in the wild. Common predators of the earthworm include birds and other small mammals.

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Biology

Schistosomiasis (Bilharziasis) is caused by some species of blood trematodes (flukes) in the genus Schistosoma. The three main species infecting humans are Schistosoma haematobium, S. japonicum, and S. mansoni. Three other species, more localized geographically, are S. mekongi, S. intercalatum, and S. guineensis (previously considered synonymous with S. intercalatum). There have also been a few reports of hybrid schistosomes of cattle origin (S. haematobium, x S. bovis, x S. curassoni, x S. mattheei) infecting humans. Unlike other trematodes, which are hermaphroditic, Schistosoma spp. are dioecous (individuals of separate sexes).

In addition, other species of schistosomes, which parasitize birds and mammals, can cause cercarial dermatitis in humans but this is clinically distinct from schistosomiasis.

Life Cycle

Schistosoma eggs are eliminated with feces or urine, depending on species . Under appropriate conditions the eggs hatch and release miracidia , which swim and penetrate specific snail intermediate hosts . The stages in the snail include two generations of sporocysts and the production of cercariae . Upon release from the snail, the infective cercariae swim, penetrate the skin of the human host , and shed their forked tails, becoming schistosomulae . The schistosomulae migrate via venous circulation to lungs, then to the heart, and then develop in the liver, exiting the liver via the portal vein system when mature, . Male and female adult worms copulate and reside in the mesenteric venules, the location of which varies by species (with some exceptions) . For instance, S. japonicum is more frequently found in the superior mesenteric veins draining the small intestine , and S. mansoni occurs more often in the inferior mesenteric veins draining the large intestine . However, both species can occupy either location and are capable of moving between sites. S. intercalatum and S. guineensis also inhabit the inferior mesenteric plexus but lower in the bowel than S. mansoni. S. haematobium most often inhabitsin the vesicular and pelvic venous plexus of the bladder , but it can also be found in the rectal venules. The females (size ranges from 7&ndash28 mm, depending on species) deposit eggs in the small venules of the portal and perivesical systems. The eggs are moved progressively toward the lumen of the intestine (S. mansoni,S. japonicum, S. mekongi, S. intercalatum/guineensis) and of the bladder and ureters (S. haematobium), and are eliminated with feces or urine, respectively .

Hosts

Various animals such as cattle, dogs, cats, rodents, pigs, horses, and goats, serve as reservoirs for S. japonicum, and dogs for S. mekongi. S. mansoni is also frequently recovered from wild primates in endemic areas but is considered primarily a human parasite and not a zoonosis.

Intermediate hosts are snails of the genera Biomphalaria, (S. mansoni), Oncomelania (S. japonicum), Bulinus (S. haematobium, S. intercalatum, S. guineensis). The only known intermediate host for S. mekongi is Neotricula aperta.

Geographic Distribution

Schistosoma mansoni is found primarily across sub-Saharan Africa and some South American countries (Brazil, Venezuela, Suriname) and the Caribbean, with sporadic reports in the Arabian Peninsula.

S. haematobium is found in Africa and pockets of the Middle East.

S. japonicum is found in China, the Philippines, and Sulawesi. Despite its name, it has long been eliminated from Japan.

The other, less common human-infecting species have relatively restricted geographic ranges. S. mekongi occurs focally in parts of Cambodia and Laos. S. intercalatum has only been found in the Democratic Republic of the Congo S. guineensis is found in West Africa. Instances of infections with hybrid/introgressed Schistosoma (S. haematobium x S. bovis, x S. curassoni, x S. mattheei) have occurred in Corsica, France, and some West African countries.

Clinical Presentation

Symptoms of schistosomiasis are not caused by the worms themselves but by the body&rsquos reaction to the eggs. Many infections are asymptomatic. A local cutaneous hypersensitivity reaction following skin penetration by cercariae may occur and appears as small, itchy maculopapular lesions. Acute schistosomiasis (Katayama fever) is a systemic hypersensitivity reaction that may occur weeks after the initial infection, especially by S. mansoni and S. japonicum. Manifestations include systemic symptoms/signs including fever, cough, abdominal pain, diarrhea, hepatosplenomegaly, and eosinophilia.

Occasionally, Schistosoma infections may lead to central nervous system lesions. Cerebral granulomatous disease may be caused by ectopic S. japonicum eggs in the brain, and granulomatous lesions around ectopic eggs in the spinal cord may occur in S. mansoni and S. haematobium infections. Continuing infection may cause granulomatous reactions and fibrosis in the affected organs (e.g., liver and spleen) with associated signs/symptoms.

Pathology associated with S. mansoni and S. japonicum schistosomiasis includes various hepatic complications from inflammation and granulomatous reactions, and occasional embolic egg granulomas in brain or spinal cord. Pathology of S. haematobium schistosomiasis includes hematuria, scarring, calcification, squamous cell carcinoma, and occasional embolic egg granulomas in brain or spinal cord.


"Flamboyant" New Squid Worm Surprises, Delights Experts

"What's that?" said scientists of the tentacle-headed swimmer. Now they know.

Scanning the depths off the Philippines in 2007, an undersea robot beamed back video of a worm—or was it a squid, or a worm eating a squid?—with spiraling appendages, iridescent "oars," and a feathery "nose."

"When the image came onto the screen, everyone said, Oh my gosh, what's that?" recalled marine zoologist Laurence Madin of the Woods Hole Oceanographic Institution in Massachusetts.

Thanks to a new study co-authored by Madin, we now have the answer. The animal—as suspected—turned out to be a bizarrely bedecked marine worm totally new to science. (See marine-worm pictures.)

The paper, published Tuesday in the journal Biology Letters, describes the new species at length for the first time and officially christens the creature Teuthidodrilus samae, or "squid worm of the Sama"—the Sama being a culture with ties to Philippine islands not far from the discovery site.

Relatively long, at nearly four inches (nine centimeters), the new annelid worm earned its moniker with a head that looks as if it's covered in tentacles.

Its front end bristles with eight arms used for breathing—each as long as the worm's entire body—and two long, loosely coiled appendages employed for feeding.

As if that weren't enough hardware, six pairs of feathery sensory organs—the squid worm's collective "nose"—protrude from the new species' head. And along the length of its body, the worm has iridescent "paddles" for propulsion.

Whatever it is, it's "definitely flamboyant," said Kristian Fauchald, curator of annelid worms at the US. National Museum of Natural History in Washington, D.C., who wasn't part of the study.

Squid Worm Caught in Full Evolutionary Flower?

Beyond its appearance, the squid worm fascinates scientists in part because its odd features suggest the worm may be a transitional form—a species caught in a burst of evolutionary adaptation as it straddles two very different habitats, said study co-author Karen Osborn, an evolutionary biologist at the University of California, Santa Cruz.

Observed between 1.2 and 1.8 miles (2 and 2.9 kilometers) below the ocean surface, Teuthidodrilus samae lives neither on the seafloor nor in the sunny shallows.

Instead, the worm inhabits a dark in-between realm, where the limited observations done so far show the worm feeding off plankton and other nutritious detritus in the water.

Whatever the cause of the squid worm's chimerical form, it apparently works. "Numerous" specimens were observed during just a few dives, the study authors write—suggesting Teuthidodrilus is common and thriving in the region.

And its homely charms apparently work on humans, or at least on worm curators.

"It has done all sorts of peculiar things to its body," Fauchald said. "I'm delighted by it."


Biology

Ascaris species are very large (adult females: 20 to 35 cm adult males: 15 to 30 cm) nematodes (roundworms) that parasitize the human intestine. A. lumbricoides is the primary species involved in human infections globally, but Ascaris derived from pigs (often referred to as A. suum) may also infect humans. These two parasites are very closely related, and hybrids have been identified thus, their status as distinct, reproductively isolated species is a contentious topic.

Life Cycle:

Adult worms live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces . Unfertilized eggs may be ingested but are not infective. Larvae develop to infectivity within fertile eggs after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed . Upon reaching the small intestine, they develop into adult worms. Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.

Hosts

Humans and swine are the major hosts for Ascaris see Causal Agents for discussion on species status of Ascaris from both hosts. Natural infections with A. lumbricoides sometimes occur in monkeys and apes.

Occasionally, Ascaris sp. eggs may be found in dog feces. This does not indicate true infection but instead spurious passage of eggs following coprophagy.

Geographic Distribution

Ascariasis is the most common human helminthic infection globally. The burden is highest in tropical and subtropical regions, especially in areas with inadequate sanitation. This infection is generally rare to absent in developed countries, but sporadic cases may occur in rural, impoverished regions of those countries. Some cases in these areas where human transmission is negligible have direct epidemiologic associations to pig farms.

Clinical Presentation

Although heavy infections in children may cause stunted growth via malnutrition, adult worms usually cause no acute symptoms. High worm burdens may cause abdominal pain and intestinal obstruction and potentially perforation in very high intensity infections. Migrating adult worms may cause symptomatic occlusion of the biliary tract, appendicitis, or nasopharyngeal expulsion, particularly in infections involving a single female worm.


by Clive A. Edwards, The Ohio State University

THE LIVING SOIL: EARTHWORMS

Of all the members of the soil food web, earthworms need the least introduction. Most people become familiar with these soft, slimy, invertebrates at a young age. Earthworms are hermaphrodites, meaning that they exhibit both male and female characteristics.

They are major decomposers of dead and decomposing organic matter, and derive their nutrition from the bacteria and fungi that grow upon these materials. They fragment organic matter and make major contributions to recycling the nutrients it contains.

Earthworms occur in most temperate soils and many tropical soils. They are divided into 23 families, more than 700 genera, and more than 7,000 species. They range from an inch to two yards in length and are found seasonally at all depths in the soil.

In terms of biomass and overall activity, earthworms dominate the world of soil invertebrates, including arthropods.

Earthworms generate tons of casts per acre each year, dramatically altering soil structure.

Credit: Clive A. Edwards, The Ohio State University, Columbus. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

A corn leaf pulled into a night crawler burrow.

Credit: Soil and Water Management Research Unit, USDA-Agricultural Research Service, St. Paul, Minnesota. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

What Do Earthworms Do?

Earthworms dramatically alter soil structure, water movement, nutrient dynamics, and plant growth. They are not essential to all healthy soil systems, but their presence is usually an indicator of a healthy system. Earthworms perform several beneficial functions.

Stimulate microbial activity. Although earthworms derive their nutrition from microorganisms, many more microorganisms are present in their feces or casts than in the organic matter that they consume. As organic matter passes through their intestines, it is fragmented and inoculated with microorganisms. Increased microbial activity facilitates the cycling of nutrients from organic matter and their conversion into forms readily taken up by plants.

Mix and aggregate soil. As they consume organic matter and mineral particles, earthworms excrete wastes in the form of casts, a type of soil aggregate. Charles Darwin calculated that earthworms can move large amounts of soil from the lower strata to the surface and also carry organic matter down into deeper soil layers. A large proportion of soil passes through the guts of earthworms, and they can turn over the top six inches (15 cm) of soil in ten to twenty years.

Increase infiltration. Earthworms enhance porosity as they move through the soil. Some species make permanent burrows deep into the soil. These burrows can persist long after the inhabitant has died, and can be a major conduit for soil drainage, particularly under heavy rainfall. At the same time, the burrows minimize surface water erosion. The horizontal burrowing of other species in the top several inches of soil increases overall porosity and drainage.

Improve water-holding capacity. By fragmenting organic matter, and increasing soil porosity and aggregation, earthworms can significantly increase the water-holding capacity of soils.

Provide channels for root growth. The channels made by deep-burrowing earthworms are lined with readily available nutrients and make it easier for roots to penetrate deep into the soil.

Bury and shred plant residue. Plant and crop residue are gradually buried by cast material deposited on the surface and as earthworms pull surface residue into their burrows.

A mixture of soil and organic matter within an earthworm burrow. Earthworms incorporate large amounts of organic matter into the soil.

Credit: Clive A. Edwards, The Ohio State University, Columbus. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Some worms live in permanent vertical burrows such as these. Others move horizontally near the surface, filling their burrow with casts as they move.

Credit: North Appalachian Experimental Watershed, USDA-Agricultural Research Service, Coshocton, Ohio. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Where Are Earthworms?

Different species of earthworms inhabit different parts of the soil and have distinct feeding strategies. They can be separated into three major ecological groups based on their feeding and burrowing habits. All three groups are common and important to soil structure.

Surface soil and litter species &ndash Epigeic species. These species live in or near surface plant litter. They are typically small and are adapted to the highly variable moisture and temperature conditions at the soil surface. The worms found in compost piles are epigeic and are unlikely to survive in the low organic matter environment of soil.

Upper soil species &ndash Endogeic species. Some species move and live in the upper soil strata and feed primarily on soil and associated organic matter (geophages). They do not have permanent burrows, and their temporary channels become filled with cast material as they move through the soil, progressively passing it through their intestines.

Deep-burrowing species &ndash Anecic species. These earthworms, which are typified by the &ldquonight crawler,&rdquo Lumbricus terrestris, inhabit more or less permanent burrow systems that may extend several meters into the soil. They feed mainly on surface litter that they pull into their burrows. They may leave plugs, organic matter, or cast (excreted soil and mineral particles) blocking the mouth of their burrows.

Looking for Earthworms?

It is easy to determine whether you have an adequate population of earthworms in your soil. Look for their casts in the forms of little piles of soil, mineral particles, or organic matter at the soil surface. They can be seen moving over the soil surface or even breeding, particularly on warm, damp nights. Dump a spade full of moist soil into a bucket or onto a sheet of plastic, and sort through for earthworms. Can you identify different species? To find the deep burrowing species, pour a dilute mustard solution onto the soil. Many will quickly come to the soil surface in response to this irritant.

Abundance and Distribution of Earthworms

The majority of temperate and many tropical soils support significant earthworm populations. A square yard of cropland in the United States can contain from 50-300 earthworms, or even larger populations in highly organic soils. A similar area of grassland or temperate woodlands will have from 100-500 earthworms. Based on their total biomass, earthworms are the predominant group of soil invertebrates in most soils.

The family of earthworms that is most important in enhancing agricultural soil is Lumbricidae, which includes the genuses Lumbricus, Aporrectodea, and several others. Lumbricids originated in Europe and have been transported by human activities to many parts of the world. The United States has only one or two known native species of lumbricids. Others were brought to this country by settlers (probably in potted plants from Europe), and were distributed down the waterways.

Generally, lumbricids are much more common in the north and east than in the drier south and west of the United States. They tend to be more abundant in loam and clay loam and even in silty soil, than in sandy soil and heavy clay. Populations also build up in irrigated soil. Earthworm populations tend to increase with soil organic matter levels and decrease with soil disturbances, such as tillage and potentially harmful chemicals.

Casts at the soil surface are evidence that earthworms are shredding, mixing, and burying surface residue.

Credit: Soil and Water Management Research Unit, USDA-Agricultural Research Service, St. Paul, Minnesota. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

This earthworm burrow is an opening in an otherwise crusted soil surface.

Credit: Clive A. Edwards, The Ohio State University, Columbus. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Interactions of Earthworms with Other Members of the Food Web

The lives of earthworms and microbes are closely intertwined. Earthworms derive their nutrition from fungi, bacteria, and possibly protozoa and nematodes, and they promote the activity of these organisms by shredding and increasing the surface area of organic matter and making it more available to small organisms.

Earthworms also influence other soil-inhabiting invertebrates by changing the amount and distribution of organic matter and microbial populations. There is good evidence that earthworm activity affects the spatial distribution of soil microarthropod communities in the soil.

Earthworms have few invertebrate enemies, other than flatworms and a species of parasitic fly. Their main predators are a wide range of birds and mammals that prey upon them at the soil surface.

Earthworms and Water Quality

Earthworms improve water infiltration and water holding capacity because their shredding, mixing, and defecating enhances soil structure. In addition, burrows provide quick entry for water into and through soil. High infiltration rates help prevent pollution by minimizing runoff, erosion, and chemical transport to surface waters.

There is concern that burrows may increase the transport of pollutants, such as nitrates or pesticides, into groundwater. However, the movement of potential pollutants through soil is not a straightforward process and it is not clear when earthworm activity will or will not have a negative impact on groundwater quality.

Whether pollutants reach groundwater depends on a number of factors, including the location of pollutants on the surface or within soil, the quantity and intensity of rain, how well water moves into and through other parts of the soil, and characteristics of the burrows. The horizontal burrows of endogeic earthworms (such as Aporrectodea tuberculata, which are common in Midwestern fields) do not transport water and solutes as deeply as the vertical burrows of night crawlers (L. terrestris) and other anecic species. Even vertical burrows, however, are not direct channels for water movement. They have bends and turns and are lined with organic matter that adsorbs many potential pollutants from the water.

Although there is much more to learn about how earthworms affect water movement through soil, they clearly help minimize pollution of surface waters by improving infiltration rates and decreasing runoff.

A mound of organic matter was moved aside to expose the entrance to a burrow. L. terrestris will quickly replug its burrow if its mound is removed.

Credit: North Appalachian Experimental Watershed, USDA-Agricultural Research Service, Coshocton, Ohio. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

L. terrestris mating, and earthworm cocoons. Earthworms mate periodically throughout the year, except when environmental conditions are unfavorable. The worms form slime tubes to help adhere to each other during copulation which may take as long as an hour.

After the worms separate, they each produce a cocoon. One or two worms will hatch from a cocoon after several weeks. L. terrestris cocoons are about a quarter inch long.

Credit: Clive A. Edwards, The Ohio State University, Columbus. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Bug Biography: Night Crawlers and Tillage

The substitution of conventional tillage by no-till or conservation tillage is increasingly common and widely adopted in the United States and elsewhere. In these situations, earthworms, particularly the &ldquonight crawler,&rdquo Lumbricus terrestris L., are especially important. Earthworms become the main agent for incorporating crop residue into the soil by pulling some into their burrows and by slowly burying the remainder under casts laid on the soil surface.

In reduced tillage systems, surface residue builds up and triggers growth in earthworm populations. Earthworms need the food and habitat provided by surface residue, and they eat the fungi that become more common in no-till soils. As earthworm populations increase, they pull more and more residue into their burrows, helping to mix organic matter into the soil, improving soil structure and water infiltration.


There is a huge variety of ways that worms are able to reproduce. In polychaetes alone, there are at least 17 known methods of reproduction, including a range of both sexual and asexual methods. Sexual reproduction, which involves two individuals, is achieved with methods such as copulation (the method humans use), broadcast spawning (where eggs are released into water to be fertilized), and epitoky (a body segment filled with gametes that floats to the surface and then releases the eggs or sperm).

Worms are often very good at regenerating themselves and reproducing asexually. Many species are able to reproduce simply by splitting in half and producing a second identical individual, a process known as transverse fission. A second common method of asexual reproduction in worms is budding, where a worm grows a fully developed individual which then separates from its ‘mother’.


The adult worm is a free-living animal. It is hairlike, very long and very thin. It commonly grows over a meter long, [3] with the record length held by a specimen of G. fulgur over two meters long, [4] and may be only about one millimeter wide. It is reddish brown to black. Besides a blunt anterior end and a slightly widened posterior end, it is featureless to the naked eye. [3] Microscopic features include a diagnostic character of the family, both Gordius and genus Acutogordius, the postcloacal crescent of the male, a fold in the cuticle curving around the back side of the cloaca. At the front end of the body there is a white cap and a dark collar. At the posterior end there are tiny bristles, sometimes arranged in a row in front of the cloaca. Some species have a smooth body surface, and some may be slightly bumpy with flattened areoles. Most of these features are used in species identification, but are not very helpful, [2] and it is difficult to tell species apart, in general. A thorough taxonomy of the genus will require a scanning electron microscope. [5]

These worms can only live near water, because parts of their life cycle take place in it. The adult overwinters in soil and debris and the female enters a water body such as a swamp or a stream to lay eggs. A gelatinous string of eggs each about 50 micrometers long is released into the water. The female can produce a great many eggs, perhaps up to 27 million in its lifetime. [3]

Juveniles require a host in which to complete their development. Upon emergence from the egg the larva swims about until it is consumed by a host insect. [3] Most Gordius worms are parasites of beetles. [4] Other recorded hosts include mantids such as the European mantis (Mantis religiosa) and Hierodula membranacea, Idolomantis diabolica, Sphodromantis viridis, and Stagmatoptera praecaria. [4] Species have been observed in caddisfly [6] and mosquito larvae. [4] Once ingested by the insect the worm larva penetrates the gut wall and develops in a cyst in the tissue outside. [4] It emerges as an adult worm in a few months. [3]

Gordius worms have been recovered from human vomit, [7] feces, [8] and urine. When worms are expelled from the gastrointestinal tract, their mode of entry was likely ingestion of contaminated food or water, or of an infested insect. When present in the urine, the worm may have entered the urethra from the anus or while the victim was swimming in contaminated water. Horsehair worms are not considered pathogenic or parasitic on humans and their presence in the body is incidental. [9]

Adult worms, as in some other Nematomorpha genera, may squirm in a tangled ball resembling a Gordian Knot horsehair worms are also referred to as gordian worms. [10]


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