Glossary and Definitions
Habitat:
categorized for each genus; may differ for species within a genus.
Feeding Mechanisms:
1. Parasitism: the food source is larger than the nematode
(parasite); the food may be extracted from individual cells or from
disrupted tissues; usually advantageous to the parasite for the food
source to remain alive, except in the case of necromeny
2. Predation:
the food source is usually smaller than the predator and is
captured, disabled or killed during the feeding process
3. Ingestion:
The food source is usually microbial or particulate and can be
ingested in the epistrate or solution in which the nematode is living.
It may be in suspension or rasped from the surface of structures prior
to ingestion.
Stomal Armaments and Feeding Structures
Teeth, Onchia, Odontia
Characteristics:
Differ in size, location, attitude, configuration among species of a
genus and among genera of a family. Usually stationary
or can be projected anteriorly by contraction of muscles
surrounding stoma or by wide dilation of stomal chamber.
Functions:
Disruption, abrasion, maceration, attachment to surfaces.
Denticles, Denticular Ridges
Characteristics:
Individual, in groups, or in bands of ridges. Usually non-moving,
Functions:
Abrasion of surfaces of prey or other food sources; maceration and
abrasion of ingested particles, microbes or larger prey.
Odontostyle, Onchiostyle, Spear
Characteristics:
Odontostyle: a protrusible hollow
stylet usually with an oblique aperture. Developmentally originating in
the esophagus wall and replacing the previous odontostyle during a
developmental molt of cuticle. Posterior to the odontostyle, and with a
contiguous lumen, is an odontophore that provides attachment for
odontostyle protractor muscles and moves forward when those muscles are
contracted.
Onchiostyle: With similar configuration as an
odontostyle, but solid, without a lumen .
Functions: Penetration of the tissues of a food
source and channeling ingested food into the esophagus, The size of the
odontostyle aperture and diameter of the lumen determine the size of
particles or microbes that can be ingested or restricted
Stomatostyle, Stylet
Characteristics:
A protrusible hollow stylet with a terminal
aperture. Developmentally originating in the stoma and replacing the
previous stomatostyle during a developmental molt of cuticle. The
stomatostyle usually consists of an anterior cone, a central shaft and
posterior knobs that provide anchorage of stylet protractor muscles.
Functions: Penetration of the cells of a food source
and channeling ingested food into the esophagus; also incising cell
walls to allow access of the nematode body. The size of the stomatostyle
aperture and diameter of the lumen limit the size of particles ingested
and, usually, limit access of bacteria and larger particle sizes.
Mandibles
Characteristics:
Hard,
strong cuticularized
structures around the stoma, sometimes
with hooks.
Functions: Biting or grasping prey to facilitate
ingestion.
Grinder
Characteristics:
Cuticular plates in the posterior bulb of the esophagus of many
bacterial-feeding nematodes.
Functions:
Crushing
or abrading microbes or particulate material prior to digestion in the
intestine.
For further definition and detail, consult
Dictionary of
Terminology
For much greater detail and analysis on nematode feeding habits and
structures, see Hodda, M. 2022. Phylum Nematoda: feeding habits for all
valid genera using a new, universal scheme encompassing the entire
phylum, with descriptions of morphological characteristics of the stoma,
a key, and discussion of the evidence for trophic relationships. Zootaxa
5114(1):318-451.
https://doi.org/10.11646/zootaxa.5114.1.3
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