How a fungal ring becomes a trap
Some soil fungi make their living by capturing nematodes—tiny, threadlike worms that move through water-filled spaces between soil particles. The fungus builds a loop from specialized cells in its threadlike body. When a nematode presses against the loop, the cells rapidly take up water and swell inward, tightening the opening around the animal.
The trigger is mechanical: contact from a passing worm sets off the trap. A constricting ring can close in a fraction of a second, too quickly for the nematode to simply back away.
From capture to meal
Once the worm is held, the fungus sends fine filaments through its body. It releases enzymes that break down the worm’s tissues, then absorbs the resulting nutrients. The captured animal becomes food that helps the fungus grow.
This is a different strategy from the sticky nets made by some other worm-trapping fungi. Those nets snag prey; the ring works by tightening around it. In both cases, the fungus turns a passing soil animal into a nutrient source—so the next time a nematode brushes a loop, a seemingly ordinary fungal thread may already be set to close.
