Estimated decrease in brood production exhibited by Bombus terrestris colonies during pulsed exposure to realistic imidacloprid residues, equivalent to those previously detected in nectar of treated crops.

Reductions are relative to the number of brood produced in undosed control colonies and were obtained using the appropriate BHM best-fit dose-response relationship from Figure 2. The reduction's 95% confidence intervals, given in parentheses, were also obtained from BHMs in Figure 2.

a

Refers to the estimated decrease in brood production expected after a 14-day exposure to imidacloprid at the given dosage.

b

Refers to the estimated total decrease in brood after a 28-day pulsed exposure at the given dosage (14 days ‘on dose’, 14 days ‘off dose’).

c

Maximum imidacloprid residues detected in the nectar of oilseed rape [21]. Data originates from studies conducted only in Member States of the European Union (OSR–Europe) and from studies including North America (OSR–USA).

d

Mean maximum level of neonicotinoid residues in nectar calculated from 20 studies [56].

e

Residues in dosed syrup used in a semi-field trial conducted by Gill et al. [8].