Fig. 3.

Pre-exposure to imidacloprid affects long-term memory (LTM) formation (massed conditioning A–C, spaced conditioning D–F). (A) After massed conditioning, bees exposed to 100 nmol l⁻¹ imidacloprid had poor performance during the short-term memory (STM, 10 min) and LTM (24 h) tests. Exposure to coumaphos (B) and a mixture of imidacloprid and coumaphos (C) did not influence recall. (D) After spaced conditioning, imidacloprid affected recall at 24 h but not at 10 min. Exposure to coumaphos (E) and a mixture of imidacloprid and coumaphos (F) did not influence recall. Note: the control group is the same for A–C and for D–F. T6, 6th conditioning trial.