By Kate Kelland

LONDON (Reuters) - Scientists in Britain have managed to teach bumblebees to pull strings to get to food and then pass on what they have learned to others in their colony - showing a high level of intelligence despite their tiny brains.

Researchers at Queen Mary University of London (QMUL) said the experiments, often used to test the intelligence of apes and birds, showed for the first time that some insects are up to the task, and can also pass skills on through several generations.

The findings add to a growing body of evidence suggesting the capacity for "culture spread" - in other words the ability to learn and pass on knowledge and skills - may not be exclusive to humans, but may also be in most animals, including insects.

"Cultural transmission does not require the high cognitive sophistication specific to humans, nor is it a distinctive feature of humans," said Clint Perry, who co-led the study.

In the research, published in the journal PLOS Biology on Tuesday, the scientists were able to train 23 out of a group of 40 bees to pull strings with their legs and feet.

The strings were attached to discs - or artificial "flowers" - containing food at their center but positioned under a transparent screen. The bees, detecting the food beneath the screen, learned to pull the "flowers" out by tugging on the string with their legs and feet to be able to get to it.

From another group of bees given the chance to solve the task without any training, only two of 110 were successful.

Another group of bees was then allowed to observe the trained bees pulling the strings - and 60 percent of them successfully learned the skill. Finally, trained bees were put in colonies and the scientists found the technique spread successfully to a majority of the colony's worker bees.

Lars Chittka, a QMUL professor who supervised the project, said the team is ultimately keen to decipher the brain processes behind the bees' learning and teaching skills.

"How can they do it with such small brains, and how can their miniature nervous systems manage such a diversity of behaviors and cognitive tasks?," he said.

(Editing by Richard Balmforth)