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. 2013 Jun 11;110(26):10693–10698. doi: 10.1073/pnas.1300954110

Table 2.

Minimal adequate linear mixed-effects model explaining the variation in the proportion of second-male sperm (S2) among all sperm retained by the female, after sequential elimination of nonsignificant random and fixed effects (Materials and Methods)

Fixed terms Estimate ± SE ddf t P
Time to ejection 0.17 ± 0.02 808.2 5.65 <0.0001
Resident sperm (first male) −0.62 ± 0.03 803.1 −19.14 <0.0001
Sperm transferred (second male) 0.55 ± 0.03 849.4 16.81 <0.0001

Following sequential elimination, the maternal isoline (LLR = 8.11, P = 0.004) and paternal isoline (LLR = 2.73, P = 0.099) were the only random effects remaining in the minimal adequate model. Conditional model R2 = 0.38; n = 855 females from 90 diallel crosses derived from 10 isolines. For full model see Table S5. Parameter estimates are standardized. Ddf, denominator degrees of freedom estimated using Satterthwaite’s approximation.