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Table 1 Summary from the linear mixed models exploring the role of social rank explaining variation in sperm design and total sperm length before manipulating the social status

From: Is sperm morphology functionally related to sperm swimming ability? A case study in a wild passerine bird with male hierarchies

 

Sperm design

Total sperm length

Fixed effects

Slope ± SD

F (df1, df2)

p

Slope ± SD

F (df1, df2)

p

Intercept

−0.79 ± 0.86

  

102.28 ± 0.79

  

Rank

 

1.72 (3,34)

0.18

 

0.88 (3,33.9)

0.46

 Subordinate 1

1.7 ± 1.23

  

1.35 ± 1.12

  

 Subordinate 2

1.43 ± 1.21

  

1.09 ± 1.1

  

 Subordinate 3

−0.66 ± 1.21

  

−0.08 ± 1.1

  

Centred body mass

0.99 ± 0.86

4.00 (1,44.6)

0.052

0.77 ± 0.79

4.82 (1,43.9)

0.033

Centred tarsus length

1.15 ± 1.71

1.10 (1,46.4)

0.30

−0.14 ± 1.57

2.70 (1,46.8)

0.11

Rank x Centred body mass

 

1.70 (3,46.4)

0.18

 

1.25 (3,46.6)

0.30

 Subordinate 1

0.65 ± 1.2

  

0.33 ± 1.1

  

 Subordinate 2

−1.76 ± 1.16

  

− 1.14 ± 1.07

  

 Subordinate 3

0.31 ± 1.09

  

0.75 ± 1.01

  

Rank x Centred tarsus length

 

0.78 (3,45.5)

0.51

 

0.46 (3,45.5)

0.71

 Subordinate 1

−3.96 ± 2.52

  

−2.11 ± 2.31

  

 Subordinate 2

−2.07 ± 2.03

  

−0.47 ± 1.86

  

 Subordinate 3

−1.83 ± 2.21

  

− 1.82 ± 2.04

  
  1. Estimates from linear mixed models, and F and p values correspond to an ANOVA using a Kenward-Roger approximation to the degrees of freedom. Contrasts are done against the means of dominant males. Bold p-values are significant (alpha = 0.05)