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.