Fig. 4
PGLS analysis of body size and gonad size. A, B Regression of testis size and ovary size on body size (left) and distribution of gonad size by inferred mating syndrome (right). The slope was significantly different from unity for the testis (i.e., negative allometry indicated by an *) but not for the ovary (see Additional file 1: Table S7 for details). C Regression of body size on gonadal sex allocation. D Distribution of body size by inferred mating syndrome. E Regression of residual testis size on residual ovary size. Points are scaled based on sample size to illustrate the weights used for the PGLS model. Color shows the inferred mating syndrome: hypodermic (yellow), intermediate (light green), reciprocal (green), and unclear (gray). Scatterplots include the fit and corresponding statistics for analysis with all species. Boxplots include results of comparing the hypodermic and reciprocal mating syndrome (excluding species assigned as intermediate and unclear) and show the second and third quartile with whiskers extending up to 1.5 times the interquartile range. R2 values represent R2pred of the full PGLS including the phylogeny