Energetic costs of parasitism in the Cape ground squirrel Xerus inauris

M. Scantlebury, J. M. Waterman, M. Hillegass, J. R. Speakman, N. C. Bennett

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

Parasites have been suggested to influence many aspects of host behaviour. Some of these effects may be mediated via their impact on host energy budgets. This impact may include effects on both energy intake and absorption as well as components of expenditure, including resting metabolic rate (RMR) and activity (e.g. grooming). Despite their potential importance, the energy costs of parasitism have seldom been directly quantified in a field setting. Here we pharmacologically treated female Cape ground squirrels (Xerus inauris) with anti-parasite drugs and measured the change in body composition, the daily energy expenditure (DEE) using doubly labelled water, the RMR by respirometry and the proportions of time spent looking for food, feeding, moving and grooming. Post-treatment animals gained an average 19 g of fat or approximately 25 kJ d(-1). DEE averaged 382 kJ d-1 prior to and 375 kJ d-1 post treatment (p> 0.05). RMR averaged 174 kJ d-1 prior to and 217 kJ d-1 post treatment (p<0.009). Post-treatment animals spent less time looking for food and grooming, but more time on feeding. A primary impact of infection by parasites could be suppression of feeding behaviour and, hence, total available energy resources. The significant elevation of RMR after treatment was unexpected. One explanation might be that parasites produce metabolic by-products that suppress RMR. Overall, these findings suggest that impacts of parasites on host energy budgets are complex and are not easily explained by simple effects such as stimulation of a costly immune response. There is currently no broadly generalizable framework available for predicting the energetic consequences of parasitic infection.

Original languageEnglish
Pages (from-to)2169-2177
Number of pages9
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume274
Issue number1622
DOIs
Publication statusPublished - 7 Sep 2007

Keywords

  • energy
  • parasite
  • ground squirrel
  • resting metabolic rate
  • doubly labelled water
  • life history
  • doubly-labeled water
  • basal metabolic-rate
  • mite spinturnix-myoti
  • laboratory mice
  • mus musculus
  • body-water
  • nippostrongylus-brasiliensis
  • oxygen-consumption
  • immune function
  • CO2 production

Cite this