Nemathelminthes and Its Feautures

Nematodes

Nematodes ( Phylum- Nemathelminthes) are simple roundworms. Colorless, unsegmented, and lacking appendages, nematodes may be free-living, predaceous, or parasitic. Many of the parasitic species cause important diseases of plants, animals, and humans. Other species are beneficial in attacking insect pests, mostly sterilizing or otherwise debilitating their hosts. A very few cause insect death but these species tend to be difficult (e.g., tetradomatids) or expensive (e.g. mermithids) to mass produce, have narrow host specificity against pests of minor economic importance, possess modest virulence (e.g., sphaeruliids) or are otherwise poorly suited to exploit for pest control purposes. The only insect-parasitic nematodes possessing an optimal balance of biological control attributes are entomopathogenic or insecticidal nematodes in the genera Steinernema and Heterorhabditis. These multi-cellular metazoans occupy a biocontrol middle ground between microbial pathogens and predators/parasitoids, and are invariably lumped with pathogens, presumably because of their symbiotic relationship with bacteria. 

Classes of Nemathelminthes:

1.Chromadorea

2. Enoplea

3. Secernentea

Major Features of Nemathelminthes:

1) They are marine or freshwater animal.

2) They are pseudocoelomate which means they have a cavity called pseudocoel between the gut and body wall.

3) They are non segmented round worm.

4) Their body is covered with cuticle .

5) They have simple type of digestive system.

6) They do not have respiratory system and circulatory system.

7) They have poorly developed nervous system.

8) They are unisexual animals.

9) They are endoparasite .

10) The mouth is provided with hooks and suckers.