Fig. 4.

Time-course of whole-body residues of fipronil (solid line) and its sulfone metabolite (dashed line) in honey bees after a single fipronil-laced meal. Body residues (y axis: mean ng·bee⁻¹) were measured in bees sampled separately at intervals over a 6-d period (x axis: days since dose) after a single acute dietary exposure to fipronil (20 μL·bee⁻¹ of syrup with 145 µg of fipronil·L⁻¹, or ca. 3 ng·bee⁻¹). Day = 0 indicates samples collected immediately after dosing and Day = −1 indicates the estimated initial fipronil ingestion. Error bars denote ±1 SEM. Mean residues are connected for ease of inspection only. Concentrations in undosed bees were less than 0.02 ng·bee⁻¹ fipronil and 0.11 ng·bee⁻¹ fipronil sulfone.