Fig. 1: No consistent evidence for senescence in ejaculate traits, irrespective of taxonomic class.

A Meta-analytical model of the overall effect of advancing male age on ejaculate traits. B Effect of advancing male age on ejaculate traits for each taxonomic class (note that animal classes with less than 25 effect sizes were grouped together in ‘Other’). The size of each data point represents the precision of the effect size (1/SE). The x-axis represents values of effect sizes as Fisher’s z-transformed correlation coefficient (Zr), while the y-axis shows the density distribution of effect sizes. The position of the overall effect is shown by the dark circle, with negative values depicting senescence in ejaculate traits and positive values showing improvement in ejaculate traits with advancing male age. Bold error bars (95% CI) show whether overall effect size is significantly different from zero (i.e. not overlapping zero), while light error bars show the 95% prediction interval (PI) of effect sizes, and black dot shows mean effect size. Sample sizes reported as: k = number of effect sizes (in brackets: number of studies). Source data is provided as a source data file.