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. 2016 Nov 29;9:616. doi: 10.1186/s13071-016-1905-7

Table 2.

Minimal adequate models for blood meal size, fecundity and survival

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]