Bumblebees Become Optimists After Sweetness 0 7

We often perceive that animals such as cats, dogs, owls, or sparrows are capable of experiencing joy or sadness. However, when it comes to invertebrates like insects, crustaceans, and worms, it is difficult for us to imagine that they can also feel emotions.

Nevertheless, upon closer analysis of their behavior, it becomes evident that some emotions, at least, are familiar to the "little bugs." For example, two years ago we discussed a study by French scientists from the National Center for Scientific Research, who found that crayfish are capable of experiencing anxiety, and their level of anxiety is directly related to the amount of the neurotransmitter serotonin, which also plays an important role in stress responses in humans and vertebrate animals.

In a new article published in the journal Science, biologists from Queen Mary University of London report on bumblebees that, as researchers discovered, become optimists after being offered syrup.

Clint J. Perry and his team conducted experiments with several dozen bumblebees, showing them plastic tubes of various colors: if the insect chose the blue tube, a treat awaited it, while if it went to the green one, it would be left empty-handed. When the bumblebees realized the difference between the green and blue tubes, the experiment was complicated: a tube of mixed blue-green color appeared before them.

Trying to determine which color was in front of them, the bumblebees hovered around the blue-green "tunnel" for quite a while — it took them about 100 seconds. However, if they had received a drop of syrup beforehand, they made their decision faster — after just 50 seconds, the bumblebee that had tasted the sweetness crawled into the ambiguous tube.

It is not that the syrup gave the bumblebees strength — their flight speed and other muscle characteristics remained the same. In fact, as the authors of the study assert, the bumblebees demonstrated an optimistic confidence arising from positive emotions — happiness, joy, and pleasure. Optimism induced by happiness is a state familiar to each of us.

In another experiment, the scientists simulated a spider attack: a special device captured a bumblebee and held it in such a way that it could not move. After being released, the bumblebee took some time to recover before going back to search for nectar. Some of them received syrup before the "attack," and it turned out that these insects recovered faster, which again confirms the presence of "syrup-induced" optimism.

If the bumblebees' dopamine receptors were blocked, there were no changes in their mood, and those who had eaten the sweetness behaved the same as those who received nothing. Dopamine is known to be responsible for the reinforcement system present in the nervous systems of many animals and is associated with feelings of reward and pleasure, including from food.

Thus, it can be concluded that the syrup activated the reinforcement system in bumblebees, and positive emotions contributed to their optimism. However, some skeptics, such as Ralph Adolphs from the California Institute of Technology, believe that sucrose itself and its metabolic products may also have influenced the insects' behavior.

For final certainty, it would be useful to directly stimulate the reinforcement system in bumblebees and observe whether their emotional state changes.