However, it appears (from analysis of mtDNA sequences, which are only inherited from the mother) that the dorippus tiger is the product of an ancient lineage of "Danaus" hybridizing with plain tiger females. As the plain tiger is known to be parasitized at least occasionally by "Spiroplasma" bacteria which selectively kill off male hosts, a subsequent scarcity of plain tiger males might have led to this hybridization and the evolution of the dorippus tiger. From the colour pattern of this species, it can be assumed that the ancient lineage had no black apex on the forewings, as this characteristic is still absent in "D. dorippus".