Fig. 1. Experimental apparatus used to train and test free-flying bees on their capacity to learn addition and subtraction.

Apparatus setup for (A) subtraction and (B) addition trials. Diagram shows parts of the Y-maze and the stimuli positions. When the bees view a yellow sample stimulus (A), they must subtract one element from it, and when the bees view a blue sample stimulus (B), they must add one element to it. (Not visible in this diagram is the entrance wall into the first chamber).