Patterns in Transmission of Marine Bird Parasites in the High Arctic: The Case of Acanthocephalans Polymorphus phippsi (Palaeacanthocephala, Polymorphidae)

Abstract

Based on materials on the infection of seabirds and invertebrates of the Franz Josef Land archipelago (FJL) collected during expeditions in 1991–1993, a species identification of the acanthocephalan Polymorphus phippsi and an analysis of the parasitic system it forms in the High Arctic were carried out. Acanthocephala is classified as hydrotopic parasites of the marine ecological group. The central link in its parasitic system is the main intermediate host—the amphipod Gammarus setosus, which is widespread in the coastal waters of the shelf zone of the entire Arctic basin. The maintenance of the acanthocephalan population in the FJL and in the European Arctic as a whole is carried out by one obligate definitive host—the common eider Somateria mollissima. The remaining bird species in which P. phippsi infection has been recorded (arctic tern, black guillemot, purple sandpiper, and several gulls) play the role of facultative and/or eliminative hosts. The flows of infection passing through different categories of hosts in the parasitic system of P. phippsi were calculated. The involvement of birds phylogenetically distant from eiders into the transmission of P. phippsi is facilitated by the trophic relationship of Arctic birds with amphipods of the coastal complex, including G. setosus. The phenomenon of nonspecific parasitism in the Arctic is also characteristic of a number of other species of avian helminths. In addition to the characteristics of the diet of birds in the Arctic, this may be determined by a decrease in their resistance to parasite infection when living in extreme Arctic conditions. It has been suggested that the parasitic systems of bird helminths in the Arctic model the situation that developed in marine coastal refugia of the late Pliocene–Pleistocene, where micro- and macroevolutionary events took place due to host radiation of parasites.