Table 2.
Summary of the effects of the treatments on the number and area of three classes of colour elements (black, orange, and yellow/cream) and on mean observer rank when males were adults at age 78 days, estimated from the posterior distributions of a Bayesian multivariate GLMM. (Family ID and body area (mm2) were included as random effects (see the electronic supplementary material, table S2 for the variance attributed to the random effects). 95% credible intervals (CIs) are included in parentheses. Mean observer rank ranged from 1 (most colourful) to 4 (least colourful). Estimated posterior means are shown for males reared without predator cues and on high-food levels as well as the estimated effects of being reared with predator cues and on low-food levels. (The estimated level of significance (pMCMC) of each effect is indicated by asterisks: *p ≤ 0.05, **p ≤ 0.01 and ***p ≤ 0.001.)
| trait later in adulthood (78 days) | mean without predator cues with high food (95% CI) | effect of predator cues (95% CI) | effect of low food (95% CI) | effect of predator cues × low food (95% CI) |
|---|---|---|---|---|
| total number black elements | 1.89 (1.71, 2.07) | −0.06 (−0.31, 0.21) | −0.02 (−0.28, 0.25) | 0.04 (−0.30, 0.41) |
| total area black elements (mm2) | 11.43 (10.08, 12.87) | −2.39 (−3.66, −1.09)*** | −0.55 (−1.88, 0.67) | 0.71 (−0.98, 2.55) |
| total number orange elements | 1.02 (0.74, 1.29) | −0.10 (−0.48, 0.29) | −0.12 (−0.52, 0.25) | 0.05 (−0.45, 0.56) |
| total area orange elements (mm2) | 5.02 (4.42, 5.54) | −1.55 (−2.05, −1.01)*** | −0.64 (−1.15, 0.05)* | 0.55 (−0.21, 1.28) |
| total number yellow/cream elements | 0.40 (0.04, 0.77) | −0.19 (−0.74, 0.30) | 0.09 (−0.36, 0.58) | −0.16 (−0.91, 0.55) |
| total area yellow/cream elements (mm2) | 1.67 (1.24, 2.14) | −0.35 (−0.86, −0.08) | −0.02 (−0.43, 0.48) | 0.27 (−0.95, 0.38) |
| mean observer rank within family | 0.30 (−0.19, 0.84) | 1.50 (0.83, 2.15)*** | 0.27 (−0.37, 0.94) | −0.04 (−0.92, 0.98) |