How did the waggle dance evolve?

17 May 2009

Question

Hello. I was watching a programme on television the other day about bees and how they do a wee dance to tell the other bees where the flowers are. I was talking about this with my friend the other night and about evolution. Neither of us could think of a way that the bee dance could have evolved small steps, if you know what I mean. Could you shed any light on that for us please?

Answer

We put this first to Andy Barron, Lecturer in the Department of Brain Behaviour and Evolution at Macquarie University. So how did the waggle dance evolve? When a forager bee has found good food, she comes back to the hive, she performs a waggle dance and these movements in the dance - very precisely and symbolically represent the direction and the distance to the food source. And then other bees are following that dancer and they read those directional-specific movements and then they head out of the hive and go and find the food. Now what we know is that performing the dance and reading the dance is entirely instinctive. So we have to infer that this whole complex, symbolic communication system is somehow programmed by the honeybee genome. Now how a genome programmes behaviour with this level of complexity I have absolutely no idea, and I don't think anybody has any idea; but there's nine honeybee species, and the dances of the dwarf honey bee:, Apis Florea - these are the most primitive honeybees - they have less complex directional information than the European Honeybee; the honeybee that we're familiar with. Maybe after millions of years this alerting signal was refined to add more space-specific information and over time you get something of a dance and symbolic as the waggle dance. But again, look, as to how the bee genome and how the bee brain have been modified by the evolutionary process to give bees this dance language, really we still have absolutely no idea, but it's a great question - it is an absolutely fantastic question.We also asked Jurgen Tautz head of the Bee Group at the University of Wurzburg in Germany.The recruitment of nest mates to food source is very important in all social insects. Most primitive we find this represented in bumblebees; where forager bumblebees, after returning to the nest, simply are just alarming their nest mates to give them the simple message: I've found something interesting to go for but there is no information whatsoever about the location. The next step then we find in stingless bees - so experienced bees which know where to go and non-experienced bees leave the nest together and they arrive at the desired location in groups. Then we find in the honeybees this dance language where bees inside the nest, tell their nest mates through this dancing movement about the geographical location. Between the stingless bee recruitment and the honeybee recruitment there's really a big gap in evolution. The reason why I think that the dance language as you find in the honeybee has evolved and not like in bumblebees or stingless bees has also to do with the precision of the nest they are building. The combs make the surfaces on which the dance is performed and these combs are extremely regular and they hang absolutely perpendicular so the direction of gravity inside the nest can be used as a direction of reference. Bumble nests are very sloppy, and stingless bees' nests, they are also not very regular so there would not have been the opportunity to evolve such a language in other closely-related species.

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