Population genomics of a threespine stickleback tapeworm in Vancouver Island

We surveyed the genetic structuring of 12 Schistocephalus solidus tapeworm populations from Vancouver Island (BC, Canada) using ddRAD sequencing and compared it to that of their threespine stickleback fish hosts. There were small but mostly significant genetic differences among the tapeworm populations. PCA results separated the populations by watershed (from the lakes where the tapeworms were collected), but we could not determine if the genetic structures seen were due to discrete models (i.e. watershed) or to a continuous model (i.e. isolation by distance). However, the tapeworm genetic differences were significantly smaller (P < 0.001) than those of the fish, which indicates that the parasite disperses more readily than their fish hosts.