Washington (AFP)
As humans can recognize by touching an object at the bottom of a congested bag, bumblebees have the ability to recognize in the dark objects they have seen previously, according to a study published Thursday in the journal Science.
These insects join other animal species which know how to use several senses to identify objects - although their brains are the size of a sesame seed, and contain only one million neurons against 100 billion in humans.
Previously, this capacity for "intermodal recognition" had been observed in primates and rats (sight and touch), dolphins (thanks to echolocation), and certain fish (electric sense).
The experiment for bumblebees, led by Cwyn Solvi, of Queen Mary University in London, and colleagues, consisted of dropping forty bumblebees in a dark room, where there was sugar water (positive reward) and a bitter quinine solution, each liquid filling either a cube or a sphere.
Bumblebees have therefore learned, in the dark, to associate a shape (a cube or a sphere) with a liquid (good or bad).
Then the bumblebees were released in an illuminated room, with the cubes and spheres covered with a plexiglass plate pierced with holes: the bumblebees could therefore see the cubes and the spheres, but not touch them. The bumblebees converged on objects containing sugar water, associating their memory by touching the new visual image.
The experiment was carried out in the other direction (light then black) and with inverted liquids, with the same results.
"Bumblebees have unified internal representations of objects in the world," Cwyn Solvi told AFP. "Their perspective on the world is more complete than if they answered only like machines".
This does not necessarily mean that bumblebees have the same level of consciousness as we do. But according to the researcher, this shows that more things are going on in their heads than we thought.
© 2020 AFP