Table 1.

Factors associated with the degree of alpha male mating monopoly. The alpha males in our study were observed to copulate with maximally swollen parous females between 47 and 303 times (mean ± s.d. = 166 ± 95). We conducted likelihood-ratio tests (LRT) to evaluate the significance of fixed effects. In each comparison, a single parameter was dropped and this reduced model was compared to the full model. Akaike Information Criterion (AIC) values in the table are model values, after the terms in the rows were dropped, one at a time. Higher AIC values indicate that dropping the particular term resulted in a model that was a worse fit to the data. The alpha ‘FG’ was the reference category for ‘alpha identity’ (ID). For Tukey contrasts between each pair of alphas, see electronic supplementary material, table S2. Variance components for the two random effects: female identity (n = 37; variance ± s.d. = 0.11 ± 0.33) and male identity (n = 27; variance ± s.d. = 148.5 ± 12.2).

parameter	estimate	s.e.	Z	d.f.	AIC	LRT	p-values
intercept	−12.881	2.223	−5.794
# males	−0.156	0.026	−5.921	1	3135.92	36.58	<0.0001
# swollen parous females	−0.140	0.068	−2.062	1	3103.65	4.32	0.038
relatedness to female	−1.885	0.266	−7.098	1	3157.97	58.64	<0.0001
alpha is focal?	1.204	0.112	10.721	1	3218.92	119.59	<0.0001
AlphaID				7	3376.85	289.52	<0.0001
AlphaID: FE	0.114	0.607	0.187
AlphaID: KS	0.366	0.585	0.626
AlphaID: SL	0.520	0.598	0.869
AlphaID: FD	1.328	0.577	2.301
AlphaID: WL	1.833	0.566	3.240
AlphaID: FR	2.179	0.577	3.778
AlphaID: GB	3.634	0.549	6.623