Gabriel Jamie and I wrote a TREE review on the persistence of polymorphisms across species radiations. Polymorphisms, i.e. the presence of different variants/morphs in the same species, are often viewed as precursors to species whereby the different morphs evolve into different species. The presence of polymorphisms has been linked to increased speciation rates. However, in this scenario, the new species should not be polymorphic anymore, as each species retains only one morph. For polymorphisms to persist through speciation events, the genetic variation needs to be present in the daughter species and the selection pressures maintaining the morphs must still act. We discuss which types of polymorphisms are likely to persist through speciation events and what factors contribute. We propose that rapid species radiations may be particularly prone to recurrent polymorphisms because lost morphs are easily reintroduced through introgression.