title: Individual growth rates in natural field vole, Microtus agrestis,  populations exhibiting cyclic population dynamics.
abstract: Rodents that have multi-annual cycles of density are known to have flexible growth strategies, and the "Chitty effect", whereby adults in the high-density phase of the cycle exhibit larger average body mass than during the low phase, is a well-documented feature of cyclic populations. Despite this, there have been no studies that have repeatedly monitored individual vole growth over time from all phases of a density cycle, in order to evaluate whether such variation in body size is due to differences in juvenile growth rates, differences in growth periods, or differential survival of particularly large or small voles. This study compares growth trajectories from voles during the peak, increase and crash phases of the cycle in order to evaluate whether voles are exhibiting fast or slow growth strategies. We found that although voles reach highest asymptotic weights in the peak phase and lowest asymptotes during the crash, initial growth rates were not significantly different. This suggests that voles attain larger body size during the peak phase as a result of growing for longer.
authors.affiliation: Biological Sciences, University of Liverpool, Liverpool, UK. sburthe@ceh.ac.uk
authors.forename: Sarah Janette
authors.initials: SJ
authors.lastname: Burthe
authors.forename: Xavier
authors.initials: X
authors.lastname: Lambin
authors.forename: Sandra
authors.initials: S
authors.lastname: Telfer
authors.forename: Alex
authors.initials: A
authors.lastname: Douglas
authors.forename: Pablo
authors.initials: P
authors.lastname: Beldomenico
authors.forename: Andrew
authors.initials: A
authors.lastname: Smith
authors.forename: Michael
authors.initials: M
authors.lastname: Begon
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000254:growth & development*; D005260:Female; D008297:Male; D011157:Population Dynamics