This is claiming more than I think is really true. They're just training the bees to avoid circles. The more circles, the less sugar water.

They're talking about zero like some highly advanced concept, probably because it took humans a while to grasp. But like others are saying, they're was always the concept of Nothing or None, and this is only how we interpreted it. Of course many animals can "comprehend" zero, but tell them to represent it and that gets a little different. Might take a while before they group the terms that they think of as 2 or None