Ectoparasites of terrestrial vertebrates inhabiting the Georgia Barrier Islands, USA: An inventory and preliminary biogeographical analysis

Aim: To document ectoparasitic arthropods of terrestrial vertebrates inhabiting barrier islands and to offer preliminary interpretations. Location: The coast of Georgia, USA, with most data presented for St Catherines, Sapelo, Jekyll, and Cumberland islands. Methods: Ectoparasites were collected and identified from hundreds of live-trapped mammals, birds, and reptiles. Ticks and louse-flies were also collected by dragging or flagging a white cloth through vegetation. Some ectoparasites were recovered from host nests or roosting sites. Literature records and specimen records from the US National Tick Collection supplemented these data. Results: Inventories of ectoparasite species recovered from vertebrates on each island are provided. Many new records and a small number of undescribed species are reported. Main conclusions: Compared with most ectoparasite faunas associated with the same host species on the adjacent mainland, ectoparasite species diversity on the barrier islands is depauperate. Possible reasons for this phenomenon are discussed including ecological, geological, and vicariant factors. Tick faunas do not appear to be depauperate on the islands probably because immature stages attach to visiting or migrating birds. Some host-ectoparasite associations that we recorded are atypical for mainland faunas. This trend has also been recorded in some previous surveys of insular ectoparasites and may be related to vacant ectoparasite niches on some islands.