The secret life of ground squirrels: Accelerometry reveals sex-dependent plasticity in above-ground activity

Cory T. Williams, Kathryn Wilsterman, Victor Zhang, Jeanette Moore, Brian M. Barnes, C. Loren Buck

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The sexes differ in how and when they allocate energy towards reproduction, but how this influences phenotypic plasticity in daily activity patterns is unclear. Here, we use collar-mounted light loggers and triaxial accelerometers to examine factors that affect time spent above ground and overall dynamic body acceleration (ODBA), an index of activity-specific energy expenditure, across the active season of free-living, semi fossorial arctic ground squirrels (Urocitellus parryii). We found high day-to-day variability in time spent above ground and ODBA with most of the variance explained by environmental conditions known to affect thermal exchange. In both years, females spent more time below ground compared with males during parturition and early lactation; however, this difference was fourfold larger in the second year, possibly, because females were in better body condition. Daily ODBA positively correlated with time spent above ground in both sexes, but females were more active per unit time above ground. Consequently, daily ODBA did not differ between the sexes when females were early in lactation, even though females were above ground three to six fewer hours each day. Further, on top of having the additional burden of milk production, ODBA data indicate females also had fragmented rest patterns and were more active during late lactation. Our results indicate that sex differences in reproductive requirements can have a substantial influence on activity patterns, but the size of this effect may be dependent on capital resources accrued during gestation.

Original languageEnglish (US)
Article number160404
JournalRoyal Society Open Science
Volume3
Issue number9
DOIs
StatePublished - Sep 2016

Keywords

  • Accelerometer
  • Activity logger
  • Arctic ground squirrel
  • Daily energy expenditure
  • Urocitellus parryii

ASJC Scopus subject areas

  • General

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