Morphology and ultrastructure of the bacterial receptacle in Steinernema nematodes (Nematoda: Steinernematidae)

► The morphology and size of the bacterial receptacles of 2-weeks old IJs varied across species. ► All examined species have a receptacle with an IVS usually composed of one cluster of acellular spheres. ► Species members of the 'feltiae' and 'intermedium' clades have a vesicle within the receptacle. ► Microvilli were present in the inner wall of the receptacle of most of the studied spp.