Scientists know that bees experience basic emotions like joy and fear, but what about more complex feelings like anxiety or depression? A group of scientists decided to try to find out.
First they trained bees to understand the difference between 2 smells.
With the first smell the bees always received a sugar reward, but with the second smell the bees got nothing. Bees can learn these associations in a few minutes, and very quickly learn to expect sugar whenever they detect the first smell, and will stick out their tongues in anticipation. This can be picked up on video camera, and is exactly the same principle as the well known Pavlov’s dog experiments.
The scientists then created a hybrid smell, which was made up of half and half of each of the 2 smells. The theory was that if bees are feeling optimistic/happy they would interpret the new smell as positive, and would stick their tongues out expecting sugar. But if bees are feeling more pessimistic/sad, they would ignore the smell and expect nothing. This provided the scientists with a sort of bee mood indicator.
They first tested the bees under normal circumstances, and then they retested the bees following a ‘stressful event’. In this case the stressful event was a vigorous shaking of the hive for 60 seconds, which scientists claim is like a badger attacking the hive. They also retested the bees at multiple time intervals after the stressful event.
And they found that the bees did indeed become noticeably more pessimistic after the shake. The scientists claim this shows that bees do experience feelings like anxiety following a stressful event. They also found that bees returned to normal very quickly after the event. One theory is that this is because it turns out honey contains a substance called chrysin, which has similar effects to Prozac, so bees seem to be creating their own anti-depressants.
While the experiments do sound a bit dubious, you can’t fault the scientist’s imagination in creating them.
One of the reasons anxiety may be an issue for bees, is that it might be linked to Colony Collapse Disorder, which started to impact the Californian almond farms in the nineties. Farmers would find hives which were completely empty of bees, with no signs of death or infection and it was as if all the bees had just disappeared. The multi-billion dollar almond industry requires billions of bees to pollinate their crops so it is a potentially huge problem.
One theory is that external stresses might be causing the bees to become anxious, and the bees then pass their anxiety to other bees via their social interactions. Eventually the whole hive is affected and if this happens then the experienced forager bees lose interest in looking for food. The younger bees try to make up the shortfall, but the younger bees are inexperienced and haven’t learnt to navigate so they are likely to get lost and die in the process. This gets worse and worse until the whole colony collapses.
Fortunately, colony collapse does not appear to be getting worse, possibly due to the improved standards of bee farming, as causes of stress include pesticides, disease, and the lack of a varied diet on the large commercial almond farms, all of which are improving.
While monitoring the bees, scientists also noticed that some bees show signs of neuro-diversity with some exhibiting differences in how they socialise and others showing repetitive behaviours. Bees are typically very quick to remove anything viewed as a genetic weakness from the hive, so the experiments might also prove that bees naturally recognise the benefits of neuro-diversity in their workforce.
