Much of what has been published about this genus is based on numerous studies of a single species, Didinium nasutum.
While D. nasutum is sometimes described as feeding exclusively upon Paramecium, it has been shown that the organism will readily devour other ciliate species, including Colpoda, Colpidium campylum, Tetrahymena pyriformis, Coleps hirtus and Lacrymaria olor [REF].