Table 3.
Statistical analysis of whole-body AChE activity (% of control) and behavior strength in different behavior responses.
| Treatments | No effects and stimulation#1 | Acclimation#2 | (Re)adjustment#3 | Toxic effect#4 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Start time (h) | AChE activity | Behavior strength | Start time (h) | AChE activity | Behavior strength | Start time (h) | AChE activity | Behavior strength | Start time (h) | AChE activity | Behavior strength | |
| 13.3 μg/L-DM | 0.0 | 95 ± 12 | 0.79 ± 0.03 | 6.0 | 82 ± 9∗∗ | 0.46 ± 0.22∗∗ | 11.0 | 49 ± 28∗∗ | 0.42 ± 0.19∗∗ | / | / | / |
| 33.40 μg/L-DM | 0.0 | 102 ± 2∗ | 0.79 ± 0.02 | 3.0 | 95 ± 5 | 0.58 ± 0.14∗∗ | 8.0 | 63 ± 27∗∗ | 0.31 ± 0.14∗∗ | 16.0 | 18 ± 17∗∗ | 0.03 ± 0.03∗∗ |
| 19.66 μg/L-MT | 0.0 | 94 ± 4 | 0.78 ± 0.03 | 5.0 | 78 ± 6∗∗ | 0.57 ± 0.09∗∗ | 11.0 | 71 ± 7∗∗ | 0.46 ± 0.07∗∗ | / | / | / |
| 49.15 μg/L-MT | 0.0 | 92 ± 11∗ | 0.79 ± 0.01 | 1.0 | 58 ± 16∗∗ | 0.44 ± 0.19∗∗ | 18.0 | 34 ± 17∗∗ | 0.25 ± 0.16∗∗ | 21.0 | 20 ± 3∗∗ | 0.27 ± 0.18∗∗ |
| Control | 0.0 | 97 ± 3 | 0.79 ± 0.04 | / | / | / | / | / | / | / | / | / |
Compared with control ∗p < 0.05 and ∗∗p < 0.01; #criteria for different stages based on the Stepwise Behavior Response Model: 1exposure period before the first significant decrease of behavior strength (SD-BS) occurred (20% [13]); 2after the first SD-BS until the first adjustment (20% behavior strength increase); 3from the first adjustment to toxic effects; 4starting from the time when behavior strength of D. magna is lower than 0.2 and there is no recovery. AChE activity data of immovable individuals in different treatments were not shown in the table.