Bumblebees show each other how to solve complex puzzles

Bumblebees can show each other how to solve a puzzle so hard they could not crack it alone. The finding suggests these insects might use advanced social learning that has previously only been demonstrated in humans.

Prior research by Alice Bridges at Queen Mary University of London suggested bumblebees could show each other how to open a lever-based puzzle to access a sugary treat. And they preferred the solution learned from peers to one they figured out independently, as if the technique were a cultural trend.

Now, Bridges has challenged the bees to a harder puzzle box that required them to manoeuvre a a blue lever and then a red one in sequence. On their own, no bees from three different colonies could figure it out – even after 12 to 14 days of trying.

Then, the researchers taught nine of the bumblebees the key – although training them was so hard the critters initially refused to participate, says Bridges, until the humans provided extra sugary rewards along the way. When reintroduced in the colony, the upskilled bees passed their new knowledge onto five other bees that had never seen the puzzle box before.

“Suddenly, [naive bees] were able to learn the whole thing from the trained demonstrator,” says Bridges. “When we could barely train [the demonstrators] to do it.”

Before this, there was little proof that non-human animals could have cumulative culture, defined as the ability to learn skills from others that they wouldn’t be able to pick up over a lifetime of independent trial and error. This feat is what allowed humans to create complex knowledge systems such as modern medicine.

These findings “cast serious doubt on this supposed human exceptionalism”, writes Alex Thornton at the University of Exeter, UK, in his commentary on the paper.

But we shouldn’t laud bees for cumulative culture just yet, says Elisa Bandini at The University of Zürich. She’s not convinced this experiment shows a behavior so complex that individual bees could not develop it on their own: if the untaught bees had also received an extra reward like the trained bees did, they might have solved the puzzle solo.