Growth patterns in free-ranging yellow-necked wood mice, Apodemus flavicollis

Growth patterns are nearly unknown in free-ranging rodents. Here we analyse growth patterns (in body length) in relation to sex, year, and population density in a population of yellow-necked wood mice, Apodemus flavicollis. This population was studied by capture-mark-recapture at a mountainous site in central Italy during 1988–1995, and 2000–2005. In our study, (i) the growth of females was accelerated compared to males of comparable body length, (ii) growth rates strongly varied inter-annually, and (iii) there was a clear density-dependence mechanism between population density and intrinsic growth rate, with growth being decelerated at density increases in both males and females. The general implications of these patterns are discussed.