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. 2025 Aug 28;36(4):araf080. doi: 10.1093/beheco/araf080

Table 2.

Linear mixed effects model results for male and female fitness and egg-to-adult viability. For the cross fixed effect (within- versus between-strain cross), estimated marginal means (emm) are shown with their standard errors (se). All measures of fitness and viability were log ratios. For fitness [egg-to-adult viability], values ~0 imply comparable numbers of brown-eye [dead] and wild-type [alive] offspring; values > 0 imply more wild-type [alive] offspring (higher fitness [viability] of experimental flies); values < 0 imply more brown-eyed [dead] offspring (lower fitness [viability] of experimental flies).

Trait Effect Cross level emm (se) Variance (x100) d.f. χ2 P
Male fitness Block (fixed, categorical) 4 154.42 <0.00001
Cross (fixed, categorical) Within 0.10 (0.16) 1 12.15 0.0005
Between 0.74 (0.10)
Fstrain (random) 0.22 1 0.00 1
Mstrain (random) 0.00 1 0.00 1
Mstrain:Fstrain (random) 22.12 1 7.76 0.0053
Residual 273.42
Female fitness Block (fixed, categorical) 4 799.11 <0.00001
Cross (fixed, categorical) Within 0.52 (0.09) 1 2.10 0.1472
Between 0.67 (0.05)
Fstrain (random) 0.00 1 0.00 1
Mstrain (random) 0.00 1 0.00 1
Mstrain:Fstrain (random) 5.25 1 6.23 0.0125
Residual 84.89
Egg-to-adult viability Block (fixed, categorical) 4 3.38 0.4967
Cross (fixed, categorical) Within 0.78 (0.16) 1 44.80 <0.00001
Between 1.65 (0.14)
Fstrain (random) 22.10 1 10.57 0.0011
Mstrain (random) 3.87 1 0.52 0.4707
Mstrain:Fstrain (random) 4.97 1 0.78 0.3758
Residual 136.20