Chewing Lice of Swan Geese (Anser cygnoides): New Host-Parasite Associations

Abstract: Chewing lice (Phthiraptera) that parasitize the globally threatened swan goose Anser cygnoides have been long recognized since the early 19th century, but those records were probably biased towards sampling of captive or domestic geese due to the small population size and limited distribution of its wild hosts. To better understand the lice species par- asitizing swan geese that are endemic to East Asia, we collected chewing lice from 14 wild geese caught at 3 lakes in northeastern Mongolia. The lice were morphologically identified as 16 Trinoton anserinum (Fabricius, 1805), 11 Ornithobi- us domesticus Arnold, 2005, and 1 Anaticola anseris (Linnaeus, 1758). These species are known from other geese and swans, but all of them were new to the swan goose. This result also indicates no overlap in lice species between older re- cords and our findings from wild birds. Thus, ectoparasites collected from domestic or captive animals may provide bi- ased information on the occurrence, prevalence, host selection, and host-ectoparasite interactions from those on wild hosts.