Table 1. Effects of exposure to clothianidin seed-treated canola fields (n = 5) on various honey bee colony endpoints.
Statistically significant effects (α = 0.05) are highlighted in bold.
| Endpoint | Effect measure | Statistics |
|---|---|---|
| SUMMER 2012 | ||
| Initial colony weight (kg) | Treatment | t8 = 1.05, P = 0.32 |
| Weight gain in canola (kg) | Treatment | t8 = −0.18, P = 0.87 |
| Honey yield (kg) | Treatment | t8 = 0.21, P = 0.84 |
| Total pollen collected (g) | Treatment | t8 = −1.63, P = 0.17 |
| Varroa mites per 100 bees | Treatment | F1,8 = 0.088, P = 0.77 |
| Time | F1,8 = 15.54, P = 0.0043 | |
| Treatment ∗ Time | F1,8 = 0.60, P = 0.46 | |
| No. dead bees (per 4 days) | Treatment | F1,8 = 0.062, P = 0.80 |
| Time | F3,6 = 11.29, P = 0.007 | |
| Treatment ∗ Time | F3,6 = 2.94, P = 0.12 | |
| No. adults | Treatment | F1,8 = 0.24, P = 0.20 |
| Time | F6,3 = 2.30, P = 0.26 | |
| Treatment ∗ Time | F6,3 = 3.12, P = 0.19 | |
| No. sealed brood cells | Treatment | F1,8 = 0.001, P = 0.92 |
| Time | F6,3 = 9.35, P = 0.047 | |
| Treatment ∗ Time | F6,3 = 0.73, P = 0.66 | |
| % canola pollen collected by bees | Treatment | F1,8 = 0.55, P = 0.47 |
| Time | F1,8 = 9.89, P = 0.014 | |
| Treatment ∗ Time | F1,8 = 0.18, P = 0.69 | |
| Amount of pollen collected daily (g) | Treatment | F1,8 = 2.64, P = 0.14 |
| Time | F5,4 = 6.80, P = 0.044 | |
| Treatment ∗ Time | F5,4 = 0.93, P = 0.54 | |
| Pollen clothianidin residues | Treatment | F1,8 = 7.62, P = 0.025 |
| Time | F1,8 = 0.60, P = 0.46 | |
| Treatment ∗ Time | F1,8 = 2.81, P = 0.13 | |
| SPRING 2013 | ||
| Overwinter mortality | Treatment | t8 = −0.69, P = 0.51 |
| No. adults | Treatment | t8 = −0.41, P = 0.69 |
| No. sealed brood cells | Treatment | t8 = −0.49, P = 0.64 |
| Nosema counts | Treatment | F1,1 = 1.18, P = 0.29 |
| Dead/Alive | F1,1 = 10.36, P = 0.003 | |
| Treatment ∗ Dead/Alive | F1,1 = 0.02, P = 0.89 |