Body condition of willow ptarmigan parasitized by cestodes during winter

• Published in: Canadian Journal of Zoology
• Main Author: Thomas, V. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1986
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Hudson Bay; Hudson
• Online Access: http://dx.doi.org/10.1139/z86-039; http://www.nrcresearchpress.com/doi/pdf/10.1139/z86-039

Sixty-two adult male willow ptarmigan (Lagopus lagopus) were collected over 3 days in April 1979 from a single flock along the Hudson Bay coast of Ontario. Twenty-one ptarmigan contained cestodes (genus Raillietina) in the anterior of the small intestine and 41 were free of cestodes. Each ptarmigan was dissected into its principal voluntary muscles, liver, and intestinal components, and the entire body was subjected to neutral fat extraction. Parasitized willow ptarmigan had significantly heavier empty small intestinal weights than nonparasitized birds. All other variables pertaining to the fat–protein reserve status were very similar between the two groups. The larger small intestines of parasitized ptarmigan were shown, statistically, to be attributable to the presence of cestodes and not to effects of varying body size. There were significant correlations between the weight of the small intestine and the weight of cestodes (r = 0.677) and the volume of cestodes (r = 0.667) but not the number of cestodes (r = 0.414) in any given ptarmigan. The hypertrophic response was confined to the small intestine and was small (approximately 1.2 g of wet tissue) compared with the amount of intestinal hypertrophy that normally occurs with change of season and diet. This population of willow ptarmigan readily accommodates to cestodes with no detectable impairment of its winter nutrient and energy balance.