Table 2.
Bayesian statistics for multivariate models with phylogeny as a random factor to test the ETH in Lake Tanganyika cichlids.
| Hypothesis tested | Parameter | Sample size Individual/species |
H2 | Posterior mean | P | |
|---|---|---|---|---|---|---|
| (1) Direct metabolic constraints | Depth | 707/71 | 0.960(0.950, 0.977) | 0.005(−0.014, 0.026) | 0.59 | |
| (2) Expensive tissue | Gut length | 490/54 | 0.971(0.961, 0.984) | −0.013(−0.022, −0.003) | 0.009 | |
| Depth | −0.006(−0.038, 0.026) | 0.70 | ||||
| Trophic guild | Inve. | 0.046(−0.030, 0.119) | 0.23 | |||
| Pisc. | 0.064(−0.048, 0.180) | 0.29 | ||||
| Scal. | −0.033(−0.207, 0.170) | 0.72 | ||||
| Zoop. | −0.019(−0.151, 0.108) | 0.75 | ||||
| (3) Energy trade-off | Egg size | 461/43 | 0.964(0.948, 0.975) | 0.030(0.001, 0.057) | 0.04 | |
| Clutch size | 707/71 | 0.979(0.971, 0.987) | 0.015(−0.006, 0.036) | 0.16 | ||
| Care duration | 373/37 | 0.879(0.818, 0.937) | 0.026(0.006, 0.043) | 0.007 | ||
The response variable is log10-transformed brain mass in both models. Sample size, H2, posterior mean, and P-value for each parameter are presented. The 95% lower credibility interval followed by the upper credible interval is also given as a superscript for H2 and posterior mean. Note that the posterior mean for continuous variables (i.e., body mass, depth, and gut) represents the partial regression coefficient, whereas the posterior mean for trophic guild represents the differential intercept coefficient comparing each category with algivore.
Abbreviations for each level of trophic guild are as follows: Inve. = invertivore; Pisc. = piscivore; Scal. = scale eater; Zoop = zooplanktivore.
All analyses also included sex and body mass as covariates, for which the results are provided in Supporting Information Table S2. Statistically significant values are indicated in bold font.