It seems bees are best motivated by both carrot and stick Alamy

Honeybees may be better at counting when they are punished for making mistakes compared to when they are simply rewarded for correct answers.

We already had some evidence suggesting bees can count up to four. But it turns out they may be capable of grasping larger numbers too.

Scarlett Howard at the University of Toulouse in France says she thought we might be underestimating the numerical abilities of bees, which prompted her colleagues to investigate further. The team first trained bees to enter a chamber from where they could see two channels with images at their ends. One channel always had an image showing four shapes, while the other had an image bearing between one and 10 shapes.


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The bees were then split into two groups. The first were trained to pick the image with four shapes, getting a reward of sweet sucrose solution for choosing that and bitter tasting quinine solution for choosing the other image. The second group were rewarded with sucrose solution for picking the four-shape image, but not penalised for choosing the other.

The team then separately tested whether the bees could identify images showing four shapes compared to images showing five, six, seven or eight shapes. They were again put in a chamber from where they could see the images at the ends of two separate channels and the researchers counted how many times the bees chose the image with four shapes.

High five

They found that only the bees that had been conditioned with both rewards and penalties could choose the image with four shapes at a level higher than chance. When choosing between images showing four and five shapes, the bees went for four 59 per cent of time, suggesting they can understand numbers beyond four.

Lars Chittka at Queen Mary University of London compares the findings to the stick and carrot method. He says when there is a punishment for getting an answer incorrect, the motivation to be correct is heightened.

Journal reference: Journal of Experimental Biology, DOI: 10.1242/jeb.205658