The nematodes or roundworms are a part of the phylum Nematoda. They are a diverse animal
phylum inhabiting in a broad range of environments. Nematodes can be very hard to distinguish and tell
them apart. They occur in mostly every habitat in all sorts of plants and animals. The total of amount of
nematoda are around one million species in the world. Nematodes have tubular digestive systems with
openings at both ends. It also has a nervous system with a pharyngeal nerve ring. The body of the
Nematodes have more than two cell layers, tissues and organs. The body of the Nematode is covered in a
complex cuticle. They normally tend to have a sexual reproduction and gonochoristic. They do not have a
circulatory system and they feed on just about anything.
There are around five different groups of Nematode which tends to be a little difficult to figure out which one is which. Below are the five different classifications of Nematodes:
Ecological Roles: Nematodes live in a vast variety of habitats, ecologically they can be divided into free living forms and parasitic forms. Free living forms have a simple life cycle involving 4 juvenile instars on the path from egg to adult. Parasitic species have developed a wide range of variations on this basic theme. The variations involve whether there is a secondary host and the amount of time spent in one or either hosts. There is also considerable variability in the way that they move from one host species to another. thus while many species lay eggs that pass out of the primary host with the faeces where they are eaten by the secondary host which then gets eaten in turn by the primary host after the Nematodes have developed. Because it is not always totally reliable that the secondary host will be eaten just as the Nematode larvae have developed into the infective stage many species have the ability to encyst themselves in the muscle or cuticle of their secondary hosts.
Human Impacts: Nematode may be beneficial or detrimental to plant health. From agricultural and horticulture perspectives, the two categories of nematodes are the predatory ones, which will kill garden pests like cutworms and corn earworm moths, and the pest nematodes, like the root-knot nematode, which attack plants, and those that act as vectors spreading plant viruses between crop plants. Predatory nematodes can be bred by soaking a specific recipe of leaves and other detritus in water, in a dark, cool place, and can even be purchased as an organic form of pest control.
phylum inhabiting in a broad range of environments. Nematodes can be very hard to distinguish and tell
them apart. They occur in mostly every habitat in all sorts of plants and animals. The total of amount of
nematoda are around one million species in the world. Nematodes have tubular digestive systems with
openings at both ends. It also has a nervous system with a pharyngeal nerve ring. The body of the
Nematodes have more than two cell layers, tissues and organs. The body of the Nematode is covered in a
complex cuticle. They normally tend to have a sexual reproduction and gonochoristic. They do not have a
circulatory system and they feed on just about anything.
There are around five different groups of Nematode which tends to be a little difficult to figure out which one is which. Below are the five different classifications of Nematodes:
- Dorylaimia exhibits a great diversity of terrestrial and freshwater species, which most are large predators or omnivorous free-living species. Some dorylaimia are plant parasites where others are animal parasites.However members of the Dorylaimia are not found in marine habitats.
- Enoplia are characterized by amphids shaped like ovals, stirrups, or pouches. Their bodies are smooth, without rings or lines. The esophagusis cylindrical and glandular.
- Spirurina
- Tylenchina
- Rhabditina
Ecological Roles: Nematodes live in a vast variety of habitats, ecologically they can be divided into free living forms and parasitic forms. Free living forms have a simple life cycle involving 4 juvenile instars on the path from egg to adult. Parasitic species have developed a wide range of variations on this basic theme. The variations involve whether there is a secondary host and the amount of time spent in one or either hosts. There is also considerable variability in the way that they move from one host species to another. thus while many species lay eggs that pass out of the primary host with the faeces where they are eaten by the secondary host which then gets eaten in turn by the primary host after the Nematodes have developed. Because it is not always totally reliable that the secondary host will be eaten just as the Nematode larvae have developed into the infective stage many species have the ability to encyst themselves in the muscle or cuticle of their secondary hosts.
Human Impacts: Nematode may be beneficial or detrimental to plant health. From agricultural and horticulture perspectives, the two categories of nematodes are the predatory ones, which will kill garden pests like cutworms and corn earworm moths, and the pest nematodes, like the root-knot nematode, which attack plants, and those that act as vectors spreading plant viruses between crop plants. Predatory nematodes can be bred by soaking a specific recipe of leaves and other detritus in water, in a dark, cool place, and can even be purchased as an organic form of pest control.