Table 3.
Statistical significances of the influence of different factors on colony development for bumble bee colonies placed in a landscape with flowering OSR grown from clothianidin treated seeds or in a landscape with OSR fields without clothianidin seed treatment
| Hive weighta | No. of workers | |
|---|---|---|
| Intercept | 571.81 ± 6.47 (<0.001) | 56.35 ± 5.97 (<0.001) |
| DAP | 37.12 ± 2.13 (<0.001) | 6.19 ± 1.44 (<0.001) |
| Treatment | 0.56 ± 7.77 (0.944) | −0.87 ± 6.31 (0.893) |
| DAP2 | −0.76 ± 0.03 (<0.001) | −0.15 ± 0.01 (<0.001) |
| Distance to OSR 400 m | −3.39 ± 6.85 (0.633) | −8.03 ± 5.87 (0.204) |
| Temperature (sum) | – | 0.091 ± 0.09 (<0.001) |
| Humidity (sum) | – | 0.14 ± 0.02 (<0.001) |
| Wind speed (sum) | 4.68 ± 1.02 (<0.001) | 0.48 ± 0.24 (0.043) |
| Rainfall (sum) | 0.92 ± 0.35 (0.009) | 0.01 ± 0.14 (0.944) |
| DAP: Treatment | −2.84 ± 1.95 (0.145) | 0.10 ± 0.15 (0.517) |
| Treatment:DAP2 | 0.07 ± 0.04 (0.070) | – |
Summary of Poisson GLMM results; Hives CE-2-2 and CE-3-2 as outliers were excluded from calculations. The intercept is the estimated mean value of the dependent variable, when all continuous variables are held at 0 and all categorical variables are held at their baseline levels. DAP2 (i.e., the quadratic term of DAP) is included in the model because exploratory data analysis indicated a quadratic relationship (a parabolic curve) between DAP and hive weight or the number of workers, respectively. Positive values indicate positive interaction, negative values indicate negative interaction, p-values in brackets. ± Standard deviation
a Temperature sum and humidity sum are all important factors (p < 0.001). They are also highly correlated with each other as shown in the correlation and variance inflation factor analysis. The coefficient estimates of these factors, however, should be interpreted with caution, as it is not possible to accurately describe the influence of single factors on the model when correlation between them occurs. Rainfall sum is an important factor for hive weight, but it does not significantly influence the number of workers