Statistics

Statistical analyses were performed using SPSS 15.0 software. All data are presented as the mean ± SEM and illustrated as bars (pooled data by genotype or age) or as dots that illustrate the individual values in each group segregated by sex and/or age, as indicated in the legends. To evaluate the effects of genotype (G) and age (A) group, a 2 × 2 factorial analysis design was applied. Differences were studied through multivariate general linear model analysis, followed by post hoc Sidak test comparisons, when possible. For categorical variables, the Fisher’s exact test with 2 × 2 and 4 × 2 designs was used. Spearman’s correlation analyzed the body size and behavioral correlates. Graphics were made with GraphPad Prism 6. To explore possible hints of sexual differences, males (squares) and females (circles) were represented with different symbols in the graphics. P-value < 0.05 was considered as statistically significant.