The nematodes constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a very broad range of environments. Unlike cnidariansand flatworms, nematodes have tubular digestive systems with openings at both ends.
Nematodes are worms that eat the bacteria growing on rotting vegetation. By definition, these smorgasbords are short-lived. Researchers wondered how such tiny creatures move long distances to the next feast. They are 1 millimeter long in most cases.
“Our study reveals a previously unknown nematode lifestyle within the guts of slugs,” Hinrich Schulenburg, a zoologist at Christian-Albrechts-Universität in Kiel, Germany, said in a statement. “The worms appear to have evolved to persist in the harsh environment of slug intestines, similar to a symbiont or even a parasite.”