Parasite tags in ecological studies of terrestrial hosts: a study on ptarmigan (Lagopus spp.) dispersal

Abstract

The spatial distributions of parasites may provide valuable information in studies on host ecology. This study was conducted in Troms County, Northern Norway, and focussed on the spatial and temporal variation in abundance of two nematode parasites, Ascaridia compar and Trichostrongylus tenuis, infecting the gastrointestinal tract of Willow Ptarmi-gan (Lagopus lagopus) and Rock Ptarmigan (Lagopus mutus). In an inland area preva-lence of A. compar varied between 52.2–78.1% in September during 6 years of sampling, and in a coastal area that was sampled for 10 years, the prevalence of T. tenuis ranged be-tween 25.0–75.4%. Both nematodes attained significantly higher prevalences in willow ptarmigan than in Rock Ptarmigan. The nematodes showed marked differences in geo-graphical distributions in September, where A. compar was common at inland localities while T. tenuis only was found in hosts at coastal islands. Practical use of these parasites as biological tags suggested a coast to inland winter dispersal in Rock Ptarmigan, especially among juvenile hens, but no dispersal was recorded in Willow Ptarmigan. The use of bio-logical tags in general and the use of nematodes as indicators of ptarmigan dispersal are discussed.