Growth autocorrelation and animal size variation

Masami Fujiwara*, Bruce E. Kendall and Roger M. Nisbet Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, USA Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, USA *Correspondence: E-mail: [email protected] Abstract It has long been recognized that variability in animal size is affected by how individual growth rate is autocorrelated in time. Earlier studies have attributed the mechanism generating the autocorrelation primarily to size-dependent growth rate and autocorrelation in resource abundance. All of these studies have shown that positive autocorrelation in individual growth rate always translates into increased variability in size. We show that energy reserves in individuals induce growth autocorrelation by acting like a low pass filter between the resource and the internal energy that is available for metabolism, growth and reproduction. However, the reserve also reduces the variance in growth rate. Consequently, reserve-induced growth autocorrelation has relatively little effect on size variability in the population, contradicting existing ideas about the relationship between the growth autocorrelation and size variability.