(ORDO NEWS) — Experiments with bumblebees have shown that they can get carried away with rolling a ball without receiving any direct reward for it. They seem to enjoy the game itself – as do the “higher” animals, including humans.
Five years ago, scientists from the group of Queen Mary University of London professor Lars Chittka showed that insects can be taught to play “football” by offering a sweet syrup reward. Even then, biologists noticed that some insects played with the ball and without any reward.
This could be indicative of their ability to exhibit play behavior , which in itself is rather unexpected for animals with rather primitive nervous systems. To verify this, Chittka and his colleagues conducted a series of new experiments.
One of these experiments was carried out with 45 bumblebees: they were placed in turn in a closed chamber, leaving free space, on the opposite side of which a feeder was placed.
The insect could move straight towards the treat or deviate from the path, looking into the part of the chamber where the tiny balls were located.
This is exactly what the bumblebees did, as it turned out: before going out for syrup, they rolled the ball from one to 117 times, voluntarily and without receiving any reward for this activity.
In another experiment, 42 bumblebees participated. They were placed in a cell with two painted “rooms”, one containing the balls and the other empty. The insects preferred to spend time in the first “room” playing with balls.
What’s more, once the color association with the balls was formed, they could be removed and the bumblebees still preferred this room over the other. The researchers also noted that juveniles play with balls longer than adults, and males – longer than females.
According to modern ideas, true play behavior should be spontaneous and voluntary, not bring any direct rewards, including access to food, mating opportunities and other benefits for adaptation and survival.
At the same time, physical activity should not be identical to the usual activity aimed at obtaining such rewards.
Finally, the game must take place in an environment that is not stressful or otherwise anomalous, and must be enjoyable in and of itself.
Lars Chittka and his co-authors made sure that all these conditions were met in the experiments. The bumblebees did not extend their noses and did not bite the balls, as they do when eating nectar or pollen, and did not show sexual behavior towards them.
The balls were far from the nest, where the insects are trying to remove foreign objects. They were not associated with a sweet reward and did not interfere with receiving it. As a result, the scientists concluded that bumblebees’ ball manipulations fully meet all the criteria for real play behavior.
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