Intrapopulation variation in boldness differs while average boldness is similar across populations of a widespread turtle

Variation in personality among conspecific animals can be found both among and within populations. Spatially varying ecological factors can lead to differences in average behaviors among populations, but can also influence the amount of variation that occurs among individuals within populations. Few studies have evaluated how the amount of variation among individuals differs among populations, and studies of interpopulation variation in personality in general often use only a low number of study populations. We tested for variation in the mean and variance in boldness across ten widely dispersed populations of Eastern Box Turtles (Terrapene carolina carolina), a declining species with high repeatability for boldness. Using standardized assays conducted in the field, we found that mean boldness did not vary significantly across populations. At the individual level, temperature, sex, and potentially the amount of human-developed land near turtles influenced mean boldness. In contrast, after correcting for covariates that influence individual boldness levels, we found that populations differed significantly in the amount of variation in boldness among individuals. These findings add to our understanding of spatial variation in personality in general and suggest future directions to evaluate the importance of this diversity within T. c. carolina and similar model systems.