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Table 1 Model selection statistics for the weight of brood masses produced by females of Onthophagus taurus

From: Maternal effects on male weaponry: female dung beetles produce major sons with longer horns when they perceive higher population density

Model

Pairwise sequential model comparisons

Fixed effects

df

log Likelihood

Likelihood ratio

P-value

Null

4

- 1153.7

  

Female weight

5

- 1133.3

40.81

< 0.0001

Female weight + M group

6

- 1132.3

2.14

0.14

Female weight + PM group + M group

7

- 1132.1

0.27

0.60

Female weight + PM group + M group +

8

- 1131.6

1.07

0.30

Female weight : PM group

Female weight + PM group + M group +

9

- 1131.5

0.10

0.75

Female weight : PM group +

Female weight : M group

Female weight + PM group + M group +

10

- 1131.5

0.01

0.91

Female weight : PM group +

Female weight : M group +

PM group : M group

Female weight + PM group + M group +

11

- 1131.3

0.47

0.50

Female weight : PM group +

Female weight : M group +

PM group : M group +

Female weight : PM group : M group

  1. Females were assigned to experimental groups that differed in population density during the pre-mating period (PM), and in the number of possible mates during the mating period (M). The effect of female weight was added as a covariate, female identity was added as a random effect in all models (estimated as 0.323 standard deviation in the full model), and the variance was modeled as a power function of the fitted vales with an estimated parameter value of 1.260 in the full model. Likelihood ratios were calculated as the absolute difference between the - 2 x log Likelihood of the two models being compared, and each model is being compared to the model that is one row above. Comparing these models in terms of their AIC values returns qualitatively similar results.