The swallowtail butterfly effect

The Norfolk Broads is the only place you are likely to see native Swallowtail butterflies in the UK today. There has, for many years, been a suggestion that it is distinct from its various European counterparts. A paper from Nabholz et al. discusses the genetics of this wonderful creature. Co-author Mark Collins (erstwhile President of the Swallowtail and Birdwing Butterfly Trust) tells me the main conclusion is that “We have confirmed beyond doubt the clear separation of our British swallowtail as a distinct subspecies.” Historically, the Swallowtail (Papilio machaon) was far more widespread, especially across East Anglia. Cambridgeshire and Suffolk were once strongholds for the species, and 19th-century reports describe vast numbers along the fenland droves between cities such as Ely and Cambridge. But agricultural intensification and habitat loss led to its absolute decline by the 1950s other than on the Broads. Collins puts this into perspective, “From our new research, the…