Mononchus genus
Dr. Charles Opperman and Aimee Salstead
Mononchus genus
Dr. Charles Opperman and Aimee Salstead
Nematodes, also called "roundworms," are a group of tiny animals found just about everywhere. Some live in the soil, some in the water, and some even live as parasites inside other animals.
Mononchus is the name of a group of nematodes. Some Mononchus species live in the water, and some on land. This kind of nematode is not a parasite.
Mononchus nematodes are predatory, meaning they feed on other animals, including other nematodes.
You can find Mononchus in damp soil, sand or gravel on the shore of a water source, or on the bottom of a lake, pond, stream, river, or marsh.
Copyright 2000, Peter Mullin
Nematodes are transparent, meaning you can see through them. If they have color, you're just seeing what they ate.
Mononchus nematodes are only about a millimeter long, so you need a microscope to see one well. Females are a little bigger than males.
As they move through soil, Mononchus looks for food. Young Mononchus eat microscopic creatures, such as protists (Amoeba, Paramecium, Euglena, etc.). Adult nematodes attack protists as well as Rotifers, Water Bears, Aquatic Worms, and other nematodes. Mononchus will even eat each other!
The mouth of a Mononchus has a "tooth" that it uses to grab prey. Then the nematode swallows it whole. The picture below shows a Mononchus attacking prey.
After mating, female nematodes lay eggs in the soil. Some species of Mononchus are hermaphrodites, meaning there are no males and females. With hermaphrodtic nematodes, both animals lay eggs after mating.
Eggs hatch in a few hours or up to several weeks, depending on the species and the temperature.
Nematode eggs are tough. They resist freezing and can survive without oxygen. Sometimes they are transported when the mud they're in sticks to a large animal's feet.
Aquatic Mononchus spend most of their time crawling through the soil, or on plants, looking for food. Nematodes are important, because they help mix up the soil, which keeps a healthy environment for plants and other animals.
Mononchus can release a sticky fluid from its tail to grab onto objects when it needs to hang on.
Copyright 2000, Peter Mullin
Predators of nematodes include small fish, insects, crustaceans (water fleas and copepods), and others.
Nematodes are not closely related to earthworms, flatworms, or other kinds of "worms." The word "worm" is used by people to describe any animals that is small, long, and skinny. There are lots of animals that fit this description, but they are very different.
Relationships in Nature:
Relationship to Humans:
Even though some nematodes are dangerous to people, Mononchus nematodes are not. They can be very helpful, since they eat other nematodes, including harmful ones. They also help the soil by moving it, which keeps everything growing.