Table 2.
Summary of generalized linear mixed-effects models (GLMMs) significance and Bayesian contrasts (BCs)
| Response variable | Overall p-MCMC |
Pairwisea |
||||||
|---|---|---|---|---|---|---|---|---|
| cowbirds – cuckoos | cuckoos – EU-hosts | cuckoos – AS-hosts | cuckoos – AM-hosts | cowbirds – EU-hosts | cowbirds – AS-hosts | cowbirds – AM-hosts | ||
| Rel. Shellvol | <0.001 | 17.5 [13.4, 21.7] | 14.6 [11.0, 18.3] | 6.9 [3.3, 10.2] | 3.3 [9.3, 17.2] | 32.1 [28.0, 36.4] | 24.4 [20.3, 28.3] | 30.8 [26.3, 35.2] |
| Rel. PLvol | <0.001 | 6.2 [2.9, 9.5] | 17.8 [15.0, 20.7] | 10.1 [7.5, 12.8] | 18.3 [15.2, 21.3] | 24.0 [20.8, 27.2] | 16.3 [13.2, 19.5] | 24.4 [20.9, 27.8] |
| Rel. MLvol | <0.001 | 11.3 [9.2, 13.5] | −2.8 [−4.7, −1.0] | −2.6 [−4.4, −0.8] | −4.9 [−7.0, −2.9] | 8.5 [6.3, 10.6] | 8.7 [6.6, 10.8] | 6.4 [4.1, 8.7] |
| PL ratio | <0.001 | −7.0 [−9.8, −4.3] | 10.2 [7.7, 12.6] | 7.0 [4.8, 9.5] | 10.2 [7.6, 12.8] | 3.2 [−0.1, 6.0] | 0.0 [−2.7, 2.7] | 3.2 [−0.1, 6.3] |
| Rel. PLshell | <0.001 | −7.8 [−9.9, −5.7] | 5.9 [4.1, 7.7] | 4.5 [2.7, 6.2] | 7.6 [5.7, 9.6] | −1.9 [−4.0, 0.2] | −3.3 [−5.3, −1.4] | −0.1 [−2.3, 2.1] |
| Rel. MLshell | <0.001 | 7.9 [5.8, 9.9] | −5.7 [−7.5, −3.9] | −4.0 [−5.7, −2.3] | −7.5 [−9.5, −5.6] | 2.1 [−0.1, 4.1] | 3.9 [1.9, 5.8] | 0.3 [−1.9, 2.5] |
| MC density | <0.001 | −12.7 [−14.7, −10.7] | 7.4 [5.8, 9.0] | 7.9 [6.2, 9.6] | 10.1 [8.4, 11.5] | −5.3 [−7.3, −3.3] | −4.8 [−6.9, −2.7] | −2.6 [−4.5, −0.7] |
| Rel. MC | <0.001 | −724 [−825, −625] | 534 [451, 614] | 636 [549, 726] | 506 [432, 586] | −189 [−294, −92] | −88 [−191, 20] | −218 [−314, −120] |
| Rel. LAB | <0.001 | 0.39 [−0.41, 1.18] | 0.99 [0.27, 1.66] | 1.48 [0.83, 2.13] | −0.04 [−0.81, 0.70] | 1.38 [0.61, 2.20] | 1.86 [1.10, 2.62] | 0.35 [−0.46, 1.21] |
| Rel. HAB | <0.001 | −2.00 [−3.19, −0.80] | 4.55 [3.51, 5.60] | 4.27 [3.27, 5.25] | 2.00 [0.84, 3.09] | 2.55 [1.36, 3.74] | 2.28 [1.13, 3.41] | 0.003 [−1.25, 1.26] |
| Rel. TAB | <0.001 | −2.15 [−3.89, −0.37] | 5.51 [4.04, 7.08] | 5.74 [4.21, 7.17] | 1.96 [0.35, 3.67] | 3.37 [1.61, 5.13] | 3.60 [1.84, 5.27] | −0.18 [−2.09, 1.70] |
| Rel. CED | <0.001 | 0.024 [−0.019, 0.064] | −0.070 [−0.105, −0.031] | −0.059 [−0.095, −0.025] | −0.102 [−0.143, −0.064] | −0.047 [−0.088, −0.006] | −0.036 [−-0.076, 0.006] | −0.078 [−0.122, −0.034] |
| 0.016 | 0.034 [−0.017, 0.082] | 0.046 [−0.001, 0.087] | 0.029 [−0.014, 0.069] | 0.035 [−0.013, 0.081] | 0.080 [0.031, 0.132] | 0.063 [−0.001 0.112] | 0.069 [−0.001 0.123] | |
| Kμ | 0.077 | overall mean value: 0.720, range: 0.400–1.150 | ||||||
| Km | 0.086 | overall mean value: 0.443, range: 0.270–0.820 | ||||||
| pfJ | 0.055 | overall mean value: 5.384, range: 3.270–8.840 | ||||||
| Mp | 0.196 | overall mean value: 0.364, range: 0.184–0.624 | ||||||
| Mg | 0.300 | overall mean value: 0.269, range: 0.075–0.687 | ||||||
| fT | 0.066 | overall mean value: 0.606, range: 0.393–0.789 | ||||||
GLMMs were performed to determine whether consistent differences exist between egg groups (American hosts, Asian hosts, European hosts, parasitic cuckoos and parasitic cowbirds) on each eggshell structural feature (response variable). BCs were performed by multiple (pairwise) comparison post-hoc tests (BCs) for mean differences. The numerical values indicate the estimated mean difference and associated 95% credible interval (BC [95%CrI]). The BCs were considered statistically significant when the 95%CrI did not overlap zero. Finally, to determine which aspects of eggshell structural variations best explain the differences between egg groups, we also conducted Multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA). The subset of selected response variables (avoiding collinearities) were: Rel. PLvol, Rel. MLvol, Rel. PLshell, Rel. CED, , Rel. LAB, Rel. HAB, and fT (see Figure S5; Tables S1 and S2). For additional details, see STAR Methods.