Sperm competition risk drives plasticity in seminal fluid composition

Table 2 Sperm competition risk but not potential mating rate impacts on ejaculate production

Term	Paired testes mass		Epididymal sperm count		Daily sperm production		Seminal vesicles mass
	F	P	F	P	F	P	F	P
SC	5.81	0.02	8.48	0.007	5.22	0.03	4.37	0.046
MR	0.06	0.81	0.12	0.73	0.09	0.76	0.21	0.65
SC × MR	0.48	0.49	0.32	0.58	1.96	0.17	0.06	0.81

Summary of ANOVAs testing for the effects of sperm competition risk (SC) and potential mating rate (MR) treatments on four ejaculate production parameters: paired testes mass, epididymal sperm count and daily sperm production (all sperm production measures), plus seminal vesicles mass (a measure of seminal fluid production, see Table 1 for details). In all cases, the degrees of freedom for each F test, d.f. = 1,28 except for daily sperm production where one subject was excluded and so d.f. = 1,27.
ANOVA analysis of variance

ISSN: 1741-7007