Scientists tracking the flight of the bumblebee have been astonished by the power of the insects' tiny brains. Let loose to find their way among five artificial flowers in a one kilometre-wide field, the bees quickly learned which routes were the most efficient. In a surprisingly short time they drew up "flight plans" that allowed them to navigate around the flowers while using as little energy as possible.
"The speed at which they learn through trial and error is quite extraordinary for bumblebees as this complex behaviour was thought to be one which only larger-brained animals were capable of," said lead scientist Professor Lars Chittka, from Queen Mary, University of London.
Tiny radar transponders mounted on the bees' backs were used to plot where the insects were flying. The artificial flowers were fitted with motion-triggered webcams, as well as landing platforms containing a drop of sugar solution to simulate nectar. To prompt the bumblebees to visit all five flowers, each sucrose drop was only big enough to fill one fifth of a bee's crop. The flowers, arranged in a pentagon, were also far enough apart to be out of reach of each other from a bee perspective.
"Using mathematical models, we dissected bees' learning process and identified how they may decipher this optimal solution without a map," said fellow Queen Mary's scientist Dr Mathieu Lihoreau, co-author of the study reported in the online journal Public Library of Science Biology. "Initially, their routes were long and complex, revisiting empty flowers several times. But, as they gained experience, the bees gradually refined their routes through trial and error. "Each time a bee tried a new route it increased its probability of reusing the new route if it was shorter than the shortest route it had tried before. Otherwise the new route was abandoned and another was tested. "After an average of 26 times each bee went foraging, which meant they tried about 20 of the 120 possible routes, they were able to select the most efficient path to visit the flowers, without computing all the possibilities."