Thermal aversive conditioning with the US applied on different structures.

<p><b>A–C)</b> Percentage of SER to the reinforced odorant (CS+, black dots) and to the non-reinforced odorant (CS−, white dots) along conditioning trials. The thermal unconditioned stimulus (65°C) was applied on: <b>A)</b> the antennae (n = 45); <b>B)</b> the mouthparts (n = 40); <b>C)</b> the front legs (n = 42). Bees learn to respond to the CS+ and not to the CS− when the thermal stimulus is provided on any of the three structures (repeated measurement ANOVA, <i>stimulus</i> x <i>trial</i> interaction: ***: p<0.001). <b>D)</b> Delta values (Δ%SER) resulting from the difference between the responses to the CS+ and to the CS− for the US applied on the three tested structures. No difference appeared in the evolution of the three curves along conditioning trials (repeated measure ANOVA, <i>stimulus x trial</i> interaction: NS).