Table 1. Feeding activity of Gammarus pulex under constant (treatment C) or pulsed (treatments A and B) exposure to imidacloprid.

				Statistics (p-value)
Experiment	Treatment	Median cumulative feeding	Units	Wilcoxon test4	Kruskal-Wallis test5
14-day	Control	0.929	leaf discs/G.pulex		0.0010
14-day	A (pulsed)1	0.286	leaf discs/G.pulex	0.010
14-day	B (pulsed)2	0.500	leaf discs/G.pulex	0.031
14-day	C (constant)	0.000	leaf discs/G.pulex	0.003
21-day	Control	103.9	mg/G.pulex		0.0023
21-day	A (pulsed)1	114.2	mg/G.pulex	0.234
21-day	B (pulsed)3	104.4	mg/G.pulex	0.731
21-day	C (constant)	44.75	mg/G.pulex	0.002

¹Pulsed treatment with a short interval in uncontaminated water between imidacloprid pulses (4 days).

²Pulsed treatment with a long interval in uncontaminated water between imidacloprid pulses (8 days).

³Pulsed treatment with a long interval in uncontaminated water between imidacloprid pulses (11 days).

⁴Between control and treatment.

⁵Among all treatments within one experiment.