Nematodes, commonly called roundworms, are fascinating and diverse animals. Most are free-living in soil or aquatic sediment (sand or mud) but many species are parasites of plants and animals.

Nematoda (nematodes) is prey of:
Fundulus heteroclitus
Stercorarius
Larus hyperboreus
Somateria
Gavia stellata
Clangula hyemalis
Tardigrada
Oxyurichthyes lonchotus
Coregonus albula
Coregonus lavaretus
macroarthropods
Nematoda
Gambusia
Heterandria formosa
Decapoda
Floridichthys carpio
Lophogobius cyprinoides
high carnivores
Actinopterygii
Copepoda
Callinectes sapidus
soil micropredators
Paralichthyes albigutta
Strongylura marina
Urophycis floridana
Prionotus scitulus
Prionotus tribulus
Gobiosoma robustum
Microgobius gulosus
Lagodon rhomboides
Leiostomus xanthurus
Syngnathus scovelli
Hippocampus zosterae
Laridae
Cyprinodon variegatus
Anatidae
Fundulus confluentus
Fundulus similis
Adinia xenica
suspended particulate carbon
Sabellidae
Serpulidae
Pholis gunnellus
Crangon crangon
Nereis diversicolor
Nereis virens

Based on studies in:
USA: Rhode Island (Marine)
Norway: Spitsbergen (Coastal)
New Zealand (Grassland)
USA: Hawaii (Swamp)
Finland (Lake or pond, Littoral)
unknown (Soil)
USA: Florida, Everglades (Estuarine)
USA: Florida (Estuarine)
Scotland (Estuarine)
USA: California, Coachella Valley (Desert or dune)

This list may not be complete but is based on published studies.

Nematoda (nematodes) preys on:
detritus
protozoa
algae
bacteria
Rotifera
Collembola
Cumacea

fungi
Nematoda
phytoplankton
Crustacea
Polychaeta
Bivalvia
Actinopterygii
bacterioplankton
Microprotozoa
POM

Based on studies in:
USA: Rhode Island (Marine)
Scotland (Lake or pond)
South Africa (Desert or dune)
Finland (Lake or pond, Littoral)
USA: Florida, Everglades (Estuarine)
Norway: Spitsbergen (Coastal)
New Zealand (Grassland)
USA: Florida (Estuarine)
unknown (Soil)

This list may not be complete but is based on published studies.

In Great Britain and/or Ireland:
Animal / predator
sticky hyphae trap of Acaulopage anamorph of Acaulopage tetraceros is predator of Nematoda

Animal / carrion / dead animal feeder
internal mycelium of Dactylella anamorph of Acrostalagmus obovatus feeds on dead Nematoda

Animal / predator
constricting ring trap of Arthrobotrys anamorph of Arthrobotrys brochopaga is predator of Nematoda

Animal / predator
adhesive network trap of Arthrobotrys anamorph of Arthrobotrys cladodes is predator of Nematoda

Animal / predator
colony of Arthrobotrys anamorph of Arthrobotrys cladodes var. macroides is predator of Nematoda

Animal / predator
adhesive network trap of Arthrobotrys anamorph of Arthrobotrys conoides is predator of Nematoda

Animal / predator
conidial trap of Arthrobotrys anamorph of Arthrobotrys dactyloides is predator of Nematoda

Animal / parasite
Arthrobotrys anamorph of Arthrobotrys flagrans parasitises live Nematoda

Animal / predator
conidial trap of Arthrobotrys anamorph of Arthrobotrys musiformis is predator of Nematoda
Other: minor host/prey

Animal / predator
conidial trap of Arthrobotrys anamorph of Arthrobotrys oligospora is predator of Nematoda

Animal / carrion / dead animal feeder
Arthrobotrys anamorph of Arthrobotrys robusta feeds on dead Nematoda

Animal / predator
colony of Arthrobotrys anamorph of Arthrobotrys scaphoides is predator of Nematoda

Animal / predator
conidial trap of Arthrobotrys anamorph of Arthrobotrys superba is predator of Nematoda

Animal / parasitoid / endoparasitoid
internal mycelium of Cephalosporium anamorph of Cephalosporium balanoides is endoparasitoid of Nematoda

Animal / predator
Cystopage lateralis is predator of Nematoda

Animal / predator
sticky network trap of Dactylaria anamorph of Dactylaria psychrophila is predator of Nematoda

Animal / parasite
Dactylella amorph of Dactylella arnaudii parasitises Nematoda

Animal / predator
sticky knob trap of Dactylella anamorph of Dactylella asthenopaga is predator of Nematoda

Animal / predator
constricting ring trap of Dactylella bembicoides is predator of Nematoda

Animal / parasite
Dactylella amorph of Dactylella candida parasitises Nematoda

Animal / predator
hyphal network trap of Dactylella anamorph of Dactylella cionopaga is predator of Nematoda

Animal / parasite
Dactylella anamorph of Dactylella heptameres parasitises Nematoda

Animal / predator
constricting ring trap of Dactylella anamorph of Dactylella heterospora is predator of Nematoda

Animal / predator
stalked knob trap of Dactylella anamorph of Dactylella leptospora is predator of Nematoda

Animal / predator
sticky lobed branches trap, often forked and sometimes looped of Dactylella anamorph of Dactylella lobata is predator of Nematoda

Animal / predator
three-dimensional adhesive network trap of Trichothecium anamorph of Geniculifera cystosporia is predator of Nematoda

Animal / parasitoid / endoparasitoid
Haptocillium rhabdosporium is endoparasitoid of Nematoda

Animal / parasite
Harposporium anguillulae parasitises Nematoda

Animal / parasitoid / endoparasitoid
internal mycelium of Harposporium anamorph of Harposporium oxycoracum is endoparasitoid of Nematoda

Animal / predator
sticky, stalked knob trap of Dactylella anamorph of Monacrosporium ellipsosporum is predator of Nematoda

Animal / parasitoid / endoparasitoid
internal mycelium of Harposporium anamorph of Nematoctonus tylosporus is endoparasitoid of Nematoda

Animal / parasitoid / endoparasitoid
internal mycelium of Paecilomyces anamorph of Paecilomyces coccosporus is endoparasitoid of Nematoda

Animal / predator
Protascus subuliformis is predator of Nematoda

Animal / predator
superficial cleistothecium of Pseudeurotium ovale is predator of Nematoda
Remarks: Other: uncertain

Animal / parasite
Rhizophydium vermicola parasitises Nematoda
Remarks: Other: uncertain

Virus / infection vector
Strawberry Latent Ringspot virus is spread by Nematoda

Animal / predator
sticky hypha trap of Stylopage anamorph of Stylopage rhynchospora is predator of Nematoda

Virus / infection vector
Tobacco Ringspot virus is spread by Nematoda

Virus / infection vector
Tomato Black Ring virus is spread by Nematoda

Virus / infection vector
Tomato Ringspot virus is spread by Nematoda

Animal / predator
sticky prehensile branch trap of Tridentaria anamorph of Tridentaria implicans is predator of Nematoda

Animal / predator
Zoopage thamnospira is predator of Nematoda

View Nematoda Tree

Relationships based on SSU rDNA sequences after Blaxter et al. 1998, 2000. See Discussion of Phylogenetic Relationships for a more traditional view.

Catapulting transports worms: nematode
 

Nematodes leap from one soil particle to another using built up surface tension to catapult themselves.

           
  "Surface tension gets put to use by a nematode, which leaps from one soil particle (through air) to another. It holds itself in a U-bent spring with a drop of water; failure of the droplet to stay together straightens it suddenly enough to catapult the nematode upward and laterally (Dusenbery 1996)." (Vogel 2003:449-450)

"The mechanism enabling entomopathogenic [insect parasitic] nematodes (Steinernema spp.) to jump is described. Jumping performance is measured and the contribution of jumping to host finding is estimated. We used the entomopathogenic nematode Steinernema carpocapsae as a model species for the genus. Nematodes jump using a two-step process of forming and contracting a loop. During loop formation, the nematode bends the anterior half of its body until the head region makes contact with the side of the body. The two body regions are held fast by the surface tension of the water film covering the nematode. When the loop is contracted, the body becomes contorted so that the cuticle kinks. This extreme bending generates and stores sufficient energy that when the surface-tension force is broken the nematode is propelled through the air. The nematode (0.558 mm in length) can jump a distance of 4.8 ± 0.8 mm (mean ± SEM) and a height of 3.9 ± 0.1 mm. The contribution of jumping to host finding varies among species and is related to the foraging strategy used by each species." (Campbell and Kaya 1999:1947)
 
Note: The video in the gallery shows the general action, but the organism is unknown.
  Learn more about this functional adaptation.

Feeding behavior increases nitrogen availability: nematodes
 

The feeding behavior of nematodes increases nitrogen availability to plants because they prey on nitrogen-hoarding bacteria and excrete excess nitrogen in a form plants can use.

   
  "What good are nematodes? Thanks to microcosm studies [small-scale replicas of ecosystems with only certain types of organisms added to sterilized soil], scientists now know that these tiny grazers may be responsible for 30 percent or more of the nitrogen released to plants, useful work that has traditionally been attributed solely to the labors of bacteria and fungi. Russell Ingham and others then in the lab of David Coleman at Colorado State University found that bacteria thrived in larger numbers when they were placed in a microcosm of grassland soils with their nematode predator. Blue grama grass grew faster, too, and initially took up more nitrogen when the nematodes were at work below. It turns out that bacterial cells contain more nitrogen than nematodes can use, so the feasting nematodes excrete a lot of it as ammonium wastes. Both the surviving bacteria and the plants clearly benefit from this extra nitrogen source. Similar results have been found in other soil types, from those of the forests of Sweden to those nourishing winter wheat fields in The Netherlands. For instance, wheat grown where both bacteria and bacteria-grazing protozoa were active grew significantly better than in soils only bacteria present. Of course, in the real world, the action never involves just two interacting types of soil creatures, but rather a whole web of predators and prey." (Baskin 1997:111-112)
  Learn more about this functional adaptation.

Body designed for burrowing: nematode
 

The body of nematodes dictates their movement techniques via a strong external cuticle, longitudinal muscles, and pressurized core.

   
  "Nematodes, or roundworms, contrast sharply with the various sorts of flatworms. They have a strong external cuticle, a normally round cross section, and longitudinal muscles only. A grotesquely large species, the intestinal parasite Ascaris, was studied by Harris and Crofton (1957). Ascaris has a normal fiber angle of about 75 degrees; being unflattened, it lives just on the curve of figure 20.2, part way down the left-hand slope. Contraction of its muscles can only shorten it further. But shortening can only happen if it decreases in volume to move down the slope, which it can't, or if the fibers stretch, which they do very little. Mainly, muscle contraction makes it much stiffer, generating internal pressures up to 30 kilopascals--around a third of an atmosphere. The hypertensive worms do get shorter, but only by about 10 percent. Nematodes can bend by contracting muscles on one side only; and this, too, increases internal pressure. Circumferential muscles are quite superfluous--the resilience of the cuticle antagonizes the action of the longitudinals. Or, looked at another way, with a pressurized core as strut, muscle on one side can antagonize muscle on the other side just as do the biceps and triceps muscles of our upper arms. The scheme permits nematodes some unpleasant life-styles such as burrowing through our flesh." (Vogel 2003:413-414)
  Learn more about this functional adaptation.

Anhydrobiosis protects during desiccation: nematodes
 

Some nematodes survive drought conditions by entering an ametabolic state known as anhydrobiosis.

   
  "Some nematodes, or round worms, undergo a similar, though less profound, form of cryptobiosis. As demonstrated by Newcastle University researcher Prof. Conrad Ellenby during a series of classic experiments, they become wholly desiccated when confronted with unfavorable external conditions, yet they revive fully when moistened." (Shuker 2001:113)
  Learn more about this functional adaptation.

Collection Sites: world map showing specimen collection locations for Nematoda

Barcode of Life Data Systems (BOLD) Stats
                                                             

Specimen Records:	4,734
Specimens with Sequences:	2,121
Specimens with Barcodes:	1,927
Public Records:	1,479
Species:	348
Species With Barcodes:	304

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