Prionchulus and Anatonchus

Predatory nematodes

Some nematodes are able to suck or injest other nematodes or other small animals. Predatory nematodes represent approximately 5% of the overall soil nematode community. In soils, predatory nematodes vary in physical size wheares, in contrast, in the marine environment predatores are frequently the largest nematodes.

In the Netherlands many nematode species occur which feed (as adults) on the smaller soil organisms, including nematodes. As juveniles they are microbivores. In a petri-dish mononchs are easily recognizable at low magnification by their mobility and bucket shaped mouth cavity.

In members of the Mononchidae, like Prionchulus, the mouth cavity is provided with a large tooth which they use to damage the cuticle of their prey; subsequently they suck the liquid content out of the prey body. In the intestine of these mononchs, remainings of the prey can be visble. Members of the Anatonchidae, Anatonchus at the lower photo, have three posterior directed teeth in the mouth cavity which prevent escaping the preys, they swallow the whole undamaged nematode which often can be observed in the intestine. In a petri-dish, mononchs appear to be very active and give the impression that mononchs offer interesting possibilities for the control of plant-parasitic nematodes. In the soil, however, they have to invest much more energy in finding their prey. The possibilities to use mononchs for biological control of plant parasites are not yet convincing.

(Source: European Atlas of Soil Biodiversity|Section2: Organisms of the Soil)

Anatonchus/Picture: Dr Neilson ©The James Hutton Institute
Anatonchus/Picture: Dr Neilson ©The James Hutton Institute

More pictures of Prionchulus punctatus (Cobb, 1917):

Prionchulus punctatus
Prionchulus punctatus

Prionchulus punctatus: oblong stoma and part of pharynx
Prionchulus punctatus: oblong stoma and part of pharynx

Prionchulus punctatus: large dorsal anterior tooth
Prionchulus punctatus: large dorsal anterior tooth
Prionchulus punctatus: head region, part of pharynx
Prionchulus punctatus: head region, part of pharynx
Prionchulus punctatus: dorsal tooth and oral cavity
Prionchulus punctatus: dorsal tooth and oral cavity
Prionchulus punctatus: subventral denticles
Prionchulus punctatus: subventral denticles
Prionchulus punctatus: female gonad
Prionchulus punctatus: female gonad
Prionchulus punctatus: eggs
Prionchulus punctatus: eggs
Prionchulus punctatus: posterior body
Prionchulus punctatus: posterior body
Prionchulus punctatus: anal opening and conoid tail
Prionchulus punctatus: anal opening and conoid tail
Prionchulus: anterior body (with prey)
Prionchulus: anterior body (with prey)
Prionchulus: mid-body
Prionchulus: mid-body

Prionchulus: posterior body
Prionchulus: posterior body
Prionchulus: feeding on prey
Prionchulus: feeding on prey
Prionchulus: feeding on prey
Prionchulus: feeding on prey

(Click on the pictures for an enlargement, © Laboratory of Nematology/Pictures: Hanny van Megen)