title: Ectoparasites and fitness of female Columbian ground squirrels.
abstract: Parasites play an important role in the evolution of host traits via natural selection, coevolution and sexually selected ornaments used in mate choice. These evolutionary scenarios assume fitness costs for hosts. To test this assumption, we conducted an ectoparasite removal experiment in free-living Columbian ground squirrels (Urocittelus columbianus) in four populations over three years. Adult females were randomly chosen to be either experimentally treated with anti-parasite treatments (spot-on solution and flea powder, N = 61) or a sham treatment (control, N = 44). We expected that experimental females would show better body condition, increased reproductive success and enhanced survival. Contrary to our expectations, body mass was not significantly different between treatments at mating, birth of litter or weaning of young. Further, neither number nor size of young at weaning differed significantly between the two treatments. Survival to the next spring for adult females and juveniles was not significantly different between experimental and control treatments. Finally, annual fitness was not affected by the treatments. We concluded that females and their offspring were able compensate for the presence of ectoparasites, suggesting little or no fitness costs of parasites for females in the different colonies and during the years of our experiments.
authors: Department of Environmental Sciences Zoology and Evolution, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland shirleyraveh@hotmail.com.
authors: Shirley
authors: S
authors: Raveh
authors: Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
authors: Peter
authors: P
authors: Neuhaus
authors: Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
authors: F Stephen
authors: FS
authors: Dobson
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001835:Body Weight; D005260:Female; D058267:Flea Infestations / Q000469:parasitology / Q000503:physiopathology / Q000662:veterinary; D056084:Genetic Fitness; D006790:Host-Parasite Interactions / Q000502:physiology; D059208:Parasite Load; D011247:Pregnancy; D012098:Reproduction; D012589:Sciuridae / Q000469:parasitology* / Q000502:physiology*; D012641:Selection, Genetic
keywords: Columbian ground squirrel; body weight; ectoparasites; parasite removal; reproduction; survival