Morphological and physiological characteristics of seven strains of yeast-like symbionts isolated from Sitodrepa panicea justify their, inclusion into the genus Torulopsis as a new species: T.buchnerii. The symbiotic relationship is mutually beneficial: the symbionts obtain some nitrogenous compounds and carbohydrates, such as proline and trehalose from the host's hemolymph, and synthesize and make available to the host all the essential amino acids and vitamins, except biotin.