Butterflies are among the best studied animals but, despite the research efforts carried out during centuries, our knowledge on the dynamics responsible for the emergence of novel diversity are still incomplete. In this context, hybridisation is classically regarded as a linear process during which two entities diverge from a common ancestor through time. Although this may be true for some cases, hybridisation is also a powerful fuel of new diversity. In this talk, I will present a case of hybrid speciation in Spialia butterflies. Spialia rosae is a recently described Iberian endemism, cryptic to the western European S. sertorius. Despite their morphological similarities, they exhibit distinct ecologies: S. rosae uses Rosa spp. as larval host plant and is a mountain specialist while S. sertorius feeds on Sanguisorba spp. and is a habitat generalist. We found that S. rosae is, in fact, genetically extremely close to S. sertorius. However, its mitochondrial genome and part of the nuclear genome are closely related with a third species, S. orbifer, nowadays ranging between Italy (Sicily) and Central Asia. This pattern highlights S. rosae as species with hybrid origin in which, the transference of genetic material from S. orbifer, would have had implications on its particular ecology and on the reproductive isolation from S. sertorius.

Trabajo presentado en el Second IBE PhD Symposium, celebrado online el 4 y 5 de febrero de 2021.