Constricting ring of a Arthrobotrys dactyloides. Constricting rings are the most sophisticated nematode-trapping devise developed by fungi. The ring is attached to a short stalk, and is composted of 3 cells. When a nematode move into the ring, it triggers off those three cells to pinch the nematode (picture is courtesy of Esser).
	Most of those nematodes that are caught are of middle size range. Small nematode can escape, whereas big nematode can’t get through the ring far enough to be pinched.
	Conidia of Arthrobotrys dactyloides are elongate-ellipsoidal, slightly curved, born in cluster at the apex of conidiophore (picture is courtesy of Esser).
	(picture is courtesy of Esser).
	Constricting ring of Arthrobotrys dactyloides trapping a spiral nematode (picture is courtesy of Esser).
	Constricting ring of Arthrobotrys dactyloides trapping a root-knot nematode (picture is courtesy of Wang).
	Constricting ring of Arthrobotrys dactyloides trapping a reniform nematode (picture is courtesy of Wang).
	Under stress conditions, codinia of Arthrobotrys dactyloides can germinate and form constricting ring directly. Persmark and Nordbring-Hertz (1997) showed that this is a strategy of the fungus over coming fungistasis (picture is courtesy of Wang).