The concept of zero, the quantity "nothing", is not immediately understandable: children often have difficulty conceiving the sense of arithmetic zero … which instead seems to be quite clear to the bees. A study conducted by researcher Scarlett Howard of RMIT University in Melbourne (Australia) and by her colleagues would indeed have shown that bees are well able to grasp the idea of zero: if this is indeed the case, they would be the first invertebrates endowed with this capacity not at all obvious.
The study, presented at the beginning of August at the 35th international conference on ethology (in Estoril, Portugal), was divided into two phases. In the first the bees were trained to identify the difference between two numbers. To achieve this, the researchers used two platforms on which 1 or 4 small objects were arranged.
The first experiment. The platform with a single object "rewarded" the bees that rested there with a sweetened liquid, while the other "punished" them by spraying them with a solution of quinine. This first experiment continued until 80% of the bees learned to choose the platform with the fewest number of objects without fail.
Researchers often changed the shape of objects to show that bees were not influenced by form but by quantity.
The ability to count. They then began to randomly vary the quantities with the same reward and punishment modalities, until it became clear that most bees alighted without hesitation on the platform that presented "zero" objects, against another that he had one to six.
In this second phase of the test a complex behavior was recognized in the choice between one and zero objects: the bees took more time to make the right decision, as if they were influenced by the reduced numerical distance - hesitation that did not manifest in the choice between zero objects and quantities greater than one.
From these behaviors the researchers deduced that bees conceive zero (no quantity) as a number like others, as happens with primates: it is instead a mystery to clarify the purpose of this ability for insects.