Table 3.
Phylogenetically corrected models testing the relationship between weapon length and testes mass, sperm dimensions and mating tactics
| Dependent variable | Independent variables | beta ± SE | t | P | N | df | r | λ |
|---|---|---|---|---|---|---|---|---|
| Weapon length |
Body mass |
0.44 ± 0.09 |
4.70 |
< 0.001 |
45 |
41 |
0.59 |
0.27
0.64/0.11
|
| |
Testes mass |
−0.04 ± 0.12 |
−0.31 |
0.76 |
|
|
−0.05 |
|
| |
Tactic |
−0.74 ± 0.60 |
−1.22 |
0.23 |
|
|
−0.19 |
|
| |
Testes mass × Tactic |
0.11 ± 0.14 |
0.74 |
0.46 |
|
|
0.12 |
|
| Weapon length |
Body mass |
0.56 ± 0.06 |
8.40 |
< 0.001 |
54 |
50 |
0.77 |
1.00
< 0.001/0.81
|
| |
Sperm length |
−1.92 ± 1.05 |
−1.83 |
0.07 |
|
|
0.25 |
|
| |
Tactic |
−5.12 ± 4.74 |
−1.08 |
0.28 |
|
|
0.15 |
|
| |
Sperm length × Tactic |
1.20 ± 1.16 |
1.04 |
0.30 |
|
|
0.15 |
|
| Weapon length |
Body mass |
0.53 ± 0.06 |
8.53 |
< 0.001 |
54 |
50 |
0.77 |
0.99
< 0.001/0.38
|
| |
Sperm head length |
0.90 ± 0.76 |
1.18 |
0.24 |
|
|
0.16 |
|
| |
Tactic |
2.14 ± 1.69 |
1.26 |
0.21 |
|
|
0.18 |
|
| |
Sperm head length × Tactic |
−1.11 ± 0.81 |
−1.37 |
0.18 |
|
|
−0.19 |
|
| Weapon length |
Body mass |
0.52 ± 0.07 |
7.50 |
< 0.001 |
53 |
49 |
0.73 |
0.98
< 0.001/0.36
|
| |
Sperm midpiece length |
−0.26 ± 0.46 |
−0.56 |
0.58 |
|
|
0.08 |
|
| |
Tactic |
−0.59 ± 1.46 |
−0.41 |
0.69 |
|
|
−0.06 |
|
| |
Sperm midpiece length × Tactic |
0.16 ± 0.58 |
0.28 |
0.78 |
|
|
0.04 |
|
| Weapon length |
Body mass |
0.49 ± 0.07 |
7.26 |
< 0.001 |
47 |
43 |
0.74 |
0.98
< 0.001/0.20
|
| |
Sperm midpiece volume |
0.08 ± 0.17 |
0.45 |
0.65 |
|
|
0.07 |
|
| |
Tactic |
−0.07 ± 0.23 |
−0.28 |
0.78 |
|
|
−0.04 |
|
| |
Sperm midpiece volume × Tactic |
−0.06 ± 0.19 |
−0.34 |
0.74 |
|
|
−0.05 |
|
| Weapon length |
Body mass |
0.55 ± 0.06 |
8.91 |
< 0.001 |
54 |
50 |
0.78 |
1.00
< 0.001/1
|
| |
Sperm tail length |
−1.44 ± 0.75 |
−1.92 |
0.06 |
|
|
−0.26 |
|
| |
Tactic |
−3.06 ± 3.14 |
−0.98 |
0.33 |
|
|
−0.14 |
|
| Sperm tail length × tactic | 0.78 ± 0.85 | 0.91 | 0.37 | 0.13 |
Female defence species is coded as 0 and territory defence is coded as 1. Models are tested with Bininda-Emonds et al. [31] phylogeny across ungulates species (both Bovidae and Cervidae pooled). r represents effect size values and λ represents the index of phylogenetic covariance (see Methods section). The superscripts following the λ value indicate p-value of likelihood ratio tests against models with λ = 0 (first position) and λ = 1 (second position). All variables were log transformed.