Bees solve complex ‘traveling salesman’ problem

October 26, 2010

Bumblebees can find the solution to a complex mathematical problem that keeps computers busy for days.

Scientists at Royal Holloway, University of London and Queen Mary, University of London have discovered that bees learn to fly the shortest possible route between flowers even if they discover the flowers in a different order. Bees are effectively solving the “traveling salesman problem,” and these are the first animals found to do this.

The traveling salesman must find the shortest route that allows him to visit all locations on his route. Computers solve it by comparing the length of all possible routes and choosing the shortest. However, bees solve it without computer assistance.

Dr Nigel Raine, from the School of Biological Sciences at Royal Holloway explains: “Foraging bees solve travelling salesman problems every day. They visit flowers at multiple locations and, because bees use lots of energy to fly, they find a route which keeps flying to a minimum.”

The team used computer controlled artificial flowers to test whether bees would follow a route defined by the order in which they discovered the flowers or if they would find the shortest route. After exploring the location of the flowers, bees quickly learned to fly the shortest route.

As well as enhancing our understanding of how bees move around the landscape pollinating crops and wild flowers, this work has other applications. Our lifestyle relies on networks such as traffic on the roads, information flow on the web and business supply chains. By understanding how bees can solve their problem with such a tiny brain we can improve our management of these everyday networks without needing lots of computer time.

Raine adds: “Despite their tiny brains, bees are capable of extraordinary feats of behaviour. We need to understand how they can solve the Travelling Salesman Problem without a computer. What shortcuts do they use?”

The research, which is due to be published in The American Naturalist this week, has been funded by the Wellcome Trust, Biotechnology and Biological Sciences Research Council, Engineering and Physical Sciences Research Council.

Adapted from materials provided by Royal Holloway University of London