(See article text) Stilbonematinae is a subfamily of the nematode worm family Desmodoridae that is notable for its symbiosis with sulfur-oxidizing bacteria.

The presence of the bacteria, which often contain intracellular inclusions of elemental sulfur, gives the worms a bright white appearance under incident light.

Many species have multicellular sensory-glandular organs in longitudinal rows along the length of the body, which secrete mucus that the bacterial symbionts are embedded in.

[4] The bacterial symbionts are chemosynthetic, gaining energy by oxidizing sulfide from the environment, and producing biomass by fixing carbon dioxide through the Calvin-Benson-Bassham cycle.

The hosts are believed to consume the bacteria as a food source, based on evidence from their stable carbon isotope ratios.