Table 2.
Categorical exposure level: no – low – high exposure | Quantitative continuous exposure level: bird parasitaemia | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Lmer | Estimate | SE | t-value | P | Lmer | Estimate | SE | t-value | P | ||
Blood meal size (square-root transformed) | Blood meal size (square-root transformed) | ||||||||||
Intercept | 0.17 | 0.87 | 0.20 | 0.845 | Intercept | 0.74 | 0.99 | 0.75 | 0.455 | ||
Body size | 1.13 | 0.25 | 4.56 | < 0.001 | Body size | 0.95 | 0.29 | 3.32 | 0.001 | ||
Bird parasitaemia | 0.14 | 0.06 | 2.40 | 0.016 | |||||||
R2 m = 3.4%; R2 c = 19.1% | R2 m = 4.5%; R2 c = 10.8% | ||||||||||
Clutch size | Clutch size | ||||||||||
Intercept | -146.28 | 48.90 | -2.99 | 0.003 | Intercept | -147.60 | 54.87 | -2.69 | 0.008 | ||
Body size | 74.58 | 14.58 | 5.24 | < 0.001 | Body size | 66.28 | 16.15 | 4.10 | < 0.001 | ||
Blood meal size | 2.76 | 0.43 | 6.36 | < 0.001 | Blood meal size | 4.81 | 0.37 | 12.97 | < 0.001 | ||
Exposure level | -30.08 | 16.65 | -1.82 | 0.076 | |||||||
Blood meal : exposure | 2.15 | 0.72 | 2.95 | 0.006 | |||||||
R2 m = 48.5%; R2 c = 50.6% | R2 m = 50.9%; R2 c = 52.5% | ||||||||||
Coxme | Exp(coef.) | SE | z-value | P | Coxme | Exp(coef.) | SE | z-value | P | ||
Survival | Survival | ||||||||||
Clutch size | 1.01 | 0.001 | 10.29 | < 0.001 | Clutch size | 1.01 | 0.001 | 9.83 | < 0.001 | ||
Glmer | Estimate | SE | z-value | P | Glmer | Estimate | SE | z-value | P | ||
Laying probability | Laying probability | ||||||||||
Intercept | -0.57 | 0.35 | -1.60 | 0.110 | Intercept | -0.56 | 0.33 | -1.67 | 0.094 | ||
Blood meal size | 0.09 | 0.02 | 4.82 | < 0.001 | Blood meal size | 0.09 | 0.02 | 4.21 | < 0.001 | ||
Exposure level | 0.064 | Bird parasitaemia | -0.45 | 0.16 | -2.86 | 0.004 | |||||
R2 m = 18.9%; R2 c = 26.4% | R2 m = 18.2%; R2 c = 18.2% |
Each response variable (blood meal size, clutch size, survival and laying probability) was analysed with exposure level as a categorical variable (unexposed – low exposure – high exposure) and as a quantitative continuous variable (bird parasitaemia). Minimal adequate models, obtained after backward model selection based on likelihood ratio tests, are given with estimate or coefficient (exponential value, Exp(coef.)), standard error (SE), t- or z-value and P-value associated with each parameter in accordance with the performed models (lmer, coxme or glmer). Marginal and conditional R2 (R2 m and R2 c, respectively) were calculated for mixed effects models according to [63]