. 2013 Sep 19;8(9):e76510. doi: 10.1371/journal.pone.0076510

Table 2. Effects of sperm competition on spermatogenic traits depending on metabolic rate.

MSMR	Dependent variable	Predictor	Slope	F	P value	λ	r	CI	n
Low	ESC	body mass	-0.17	0.20	0.66	<0.01^{n.s., n.s.}	0.14	-0.48 to 0.76	13
		testes mass	0.27	2.86	0.12		0.47	-0.11 to 1.13
Low	SECL	body mass	0.07	4.25	0.053	<0.01^{n.s., n.s.}	0.42	0.01 to 0.88	23
		testes mass	-0.06	2.10	0.16		0.31	-0.12 to 0.76
Low	SpCauda	body mass	-0.61	0.41	0.53	0.84^{n.s., n.s.}	0.18	-0.37 to 0.72	16
		testes mass	1.61	26.29	0.0002		0.82	0.61 to 1.69
High	ESC	body mass	-0.29	7.53	0.023	<0.01^{n.s., *}	0.68	0.17 to 1.47	12
		testes mass	0.37	14.02	0.005		0.78	0.39 to 1.70
High	SECL	body mass	0.15	7.00	0.015	0.94^{*, n.s.}	0.50	0.12 to 0.98	24
		testes mass	-0.13	12.19	0.002		0.61	0.28 to 1.13
High	SpCauda	body mass	-0.54	36.52	<0.0001	<0.01^{n.s., n.s.}	0.87	0.76 to 1.89	15
		testes mass	1.67	39.7	<0.0001		0.88	0.79 to 1.93

Phylogenetically controlled multiple regression analyses revealing the effect of relative testes mass on spermatogenic traits in species with low and high mass-specific metabolic rates (MSMR). All variables were log₁₀-transformed prior to analysis. The superscripts following the λ value indicate significance levels (n.s., p > 0.05; * p < 0.05) in likelihood ratio tests against models with λ = 0 (first superscript) and λ = 1 (second superscript). The effect size r was calculated from the F values; we also present the non-central 95% confidence interval (CI), an interval excluding 0 indicating statistically significant relationships. The P values and CI that indicate statistical significance are shown in bold. Abbreviations: n: number of species in each analysis; ESC: efficiency of Sertoli cells (number of round spermatids / Sertoli cell); SECL: seminiferous epithelium cycle length; SpCauda: number of sperm in the cauda epididymides.