Honeybees exhibit pessimism

Agitated or stressed bees are more likely to be pessimistic about the world say researchers from Newcastle University.

Evidence of emotion and pessimistic outcomes are not unique to humans – they have been observed in dogs, rats, even birds – and now in honey bees too.

“We have shown that the emotional responses of bees to an adverse event are more similar to those of humans than previously thought,” said Dr Geraldine Wright. “Bees stressed by a simulated predator attack exhibit pessimism mirroring that seen in depressed and anxious people.”

Researchers from the Institute of Neuroscience wanted to find out how honeybees view the world, and trained them to make a decision about whether a smell equalled something good or bad. Bees learned to connect one odour with a sweet reward, and the other with the bitter taste of quinine. As they learned the difference, bees were more likely to go for the sweet smell.

Next the bees were divided into two groups – one was shaken violently to simulate a predator attack on the hive, and the other was left undisturbed. Both groups were then presented with the familiar smells, and new ones created from the mixture of the two.

Agitated bees were less likely than the controls to extend their mouthparts to the quinine-predicting odours – in other words, they presumed everything would taste bitter, demonstrating a cognitive bias say the researchers.

“What we have shown is that when a honeybee is subjected to a manipulation of its state that in humans would induce a feeling of anxiety, the bees show a similar suite of changes in physiology, cognition and behaviour to those we would measure in an anxious human,” Wright said. “In terms of what we are able to measure, a shaken honeybee is no less ‘anxious’ than a lonely dog or rat in a barren cage."

The researchers do not believe the finding to be unique and would expect to see the same thing in any animal that needs to change its behaviour in the face of potential dangers.