Table 1

Relations between sperm competition, sperm dimensions and swimming velocity across Eutherian mammals

Dependent variable

Predictor

Slope

F

p

λ

r

CLs

n


total sperm length

body mass

-8.21

1.06

0.3044

0.999 *, n.s.

0.07

-0.06 to 0.20

226

testes mass

8.24

3.99

0.0471

0.13

0.00 to 0.26

head length

body mass

0.74

0.39

0.5317

0.946 *, n.s.

0.05

-0.10 to 0.19

194

testes mass

0.86

6.53

0.0114

0.18

0.04 to 0.33

midpiece length

body mass

-2.63

0.14

0.7116

0.945 *, n.s.

0.03

-0.12 to 0.17

194

testes mass

3.18

3.41

0.0665

0.13

-0.01 to 0.27

principal piece length

body mass

-7.57

2.04

0.1547

0.956 *, n.s.

0.10

-0.04 to 0.25

194

testes mass

7.32

5.62

0.0188

0.17

0.03 to 0.31

total flagellum length

body mass

-8.99

0.89

0.3456

0.999 *, n.s.

0.07

-0.07 to 0.21

194

testes mass

9.61

5.32

0.0222

0.16

0.02 to 0.31

head length/head width

body mass

-0.50

0.14

0.7076

0.783 *, *

0.04

-0.18 to 0.27

79

testes mass

0.56

5.72

0.0193

0.26

0.05 to 0.50

straight line velocity

body mass

-39.86

2.08

0.1624

0.880 n.s., n.s.

0.29

-0.11 to 0.71

26

testes mass

45.71

10.56

0.0035

0.56

0.23 to 1.04

straight line velocity

total sperm length

0.72

29.66

<0.0001

<0.001 n.s., n.s.

0.74

0.55 to 1.37

26

straight line velocity

head length/flagellum length

-635.59

10.55

0.0047

<0.001 n.s., n.s.

0.62

0.23 to 1.21

19


Phylogenetically controlled multiple regression analyses revealing the effect of relative testes mass on sperm dimensions and sperm velocity, and the effect of sperm length and the proportion between sperm head and flagellum on sperm velocity. The superscripts following the λ value indicate significance levels (n.s. p > 0.05; * p < 0.05) in a likelihood ratio tests against models with λ = 0 (first position) and λ = 1 (second position). The effect size r calculated from the F values and its non-central 95% confidence limits (CLs) are presented. Confidence intervals excluding 0 indicate statistically significant relationships. The p values and CL that indicate statistical significance are shown in bold. Abbreviations: n: number of species in each analysis.

Tourmente et al. BMC Evolutionary Biology 2011 11:12   doi:10.1186/1471-2148-11-12

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