When people feel depressed or anxious, they are much more likely to see their glass as half empty rather than half full.
Evidence of this same pessimistic outlook has been shown in dogs, rats, and birds. Now, researchers have shown that bees, too, behave in a manner indicating they may also be experiencing similar negative emotions.
"We have shown that the emotional responses of bees to an aversive event are more similar to those of humans than previously thought," said Geraldine Wright of Newcastle University. "Bees stressed by a simulated predator attack exhibit pessimism mirroring that seen in depressed and anxious people." Melissa Bateson added: "In other words, the stressed bee's glass is half empty."
But, they say, that isn't the same as saying that bees consciously experience emotions in the way that we do. On that point, the jury is still out.
To find out how bees view the world, the researchers set them up to make a decision about whether an unfamiliar scent predicted good or bad things.
First, the bees were trained to connect one odour with a sweet reward and another with a bitter taste. The bees learned the difference between the odours and became more likely to extend their mouthparts to the odour predicting the sweet taste rather than the bitter one.
Next, the researchers divided the bees into two groups. One group was shaken violently for one minute to simulate an assault on the hive by a predator such as a honey badger. The other group was left undisturbed. Those bees were then presented with the familiar odours and some new ones created from mixes of the two.
Agitated bees were less likely than the other bees to extend their mouthparts to the odour predicting the bitter taste and similar new odours, the researchers found. In other words, the agitated bees behaved as if they had an increased expectation of a bitter taste, demonstrating a type of pessimistic judgment of the world known as a ‘cognitive bias’.
"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 behavior to those we would measure in an anxious human," Wright said. "In terms of what we are able to measure, a shaken honeybees is no less 'anxious' than a lonely dog or a rat in a barren cage."
The researchers say they don't expect the findings will be unique to honeybees among invertebrates. They would in fact expect to see the same thing in any animal that needs to change its behaviour in the face of potential dangers.
The findings suggest that it may be possible to study bees as a model for emotion in invertebrates. "If some scientific research on emotion could be conducted in insects, this would lead to a reduction in the numbers of sentient vertebrate animals used in research," Bateson said. "Thus our research potentially has important implications for animal welfare."
OneKind believes that we should always give animals the benefit of the doubt when our actions impact upon them. Scientific research is increasingly removing any doubt when it comes to the capacities of animals as sentient creatures. As science provides more and more evidence we must constantly re-assess and improve our the way we treat all vertebrate and invertebrate animals.