Meeting Abstract

19.4  Tuesday, Jan. 4  Ectoparasite Removal Improves Reproductive Success And Body Condition In A Territorial Tree Squirrel PATTERSON, J. E. H.; University of Calgary jesse.patterson@ucalgary.ca

Parasites are widely considered to be detrimental to the fitness of their hosts; however, the actual costs of parasitism on host fitness are rarely quantified. I experimentally removed ectoparasites from nine pregnant North American red squirrels (Tamiasciurus hudsonicus), a territorial sciurid, in Alberta, Canada. Ectoparasites were removed from mothers for three months (May-August) by use of an ectoparasite-specific topical agent applied every 30 days from the birth of offspring through to offspring weaning. Body mass of mothers and their offspring, as well as litter size were compared with nine untreated (control) mothers. Ectoparasite removal led to a non-significant increase in mean body mass of mothers during lactation and a significant increase in body mass of mothers at the time of weaning. Offspring raised by mothers treated for ectoparasites were heavier than control offspring at emergence. Treated mothers not only raised offspring in better condition than controls, but they also reared more offspring through to emergence. Control mothers lost on average 2.0 offspring between birth and emergence, whereas treated mothers lost an average of 0.4 offspring. My results indicate that ectoparasites impose strong costs on the reproductive success and body condition of female red squirrels, suggesting that ectoparasites have the potential to influence red squirrel population dynamics.