Table 1

General Linear Mixed Model results for the effects of group size (nominal factor) and density (continuous factor) on mating behaviour and fitness components.

Parameters

df

Type III SS

F

P

R²

Mate encounter rate (per individual & day)

Full model (linear)

7

3208.68

16.36

< 0.001

0.63

Group size

2

1554.93

27.75

< 0.001

Density

1

1134.29

40.49

< 0.001

Run

4

479.22

4.28

0.004

Error

66

1848.92

log Mating rate (per individual & day)

Full model (linear)

7

4.16

4.05

< 0.001

0.30

Group size

2

0.17

0.56

0.57

Density

1

0.41

2.82

0.10

Run

4

3.52

6.00

< 0.001

Error

66

9.69

Average egg mass weight

Full model (quadratic)

8

2347.63

3.60

0.002

0.31

Group size

2

4.47

0.03

0.97

Density

1

112.08

1.38

0.24

(Density)²

1

1189.43

14.61

< 0.001

Run

4

1162.98

3.57

0.01

Error

65

5291.15

Total egg mass weight per individual

Full model (linear)

7

10019.56

9.21

< 0.001

0.49

Group size

2

235.63

0.76

0.47

Density

1

12.34

0.08

0.78

Run

4

9772.64

15.72

< 0.001

Error

66

10254.59

N egg masses per individual

Full model (linear)

7

49.08

17.97

< 0.001

0.66

Group size

2

0.53

0.68

0.51

Density

1

0.04

0.11

0.74

Run

4

48.44

31.03

< 0.001

Error

66

25.75

Significant P-values are indicated in bold. Note that interaction terms with P ≥ 0.25 were removed from the analysis (see Material and Methods for details).

Sprenger et al. BMC Evolutionary Biology 2011 11:107   doi:10.1186/1471-2148-11-107