Wednesday, 1 August 2012

Ants, Bees and Brains

Alicja Jedrzejewska

Ants, bees and brains, or more specifically rock ants, honeybees and neurones, have surprisingly a lot in common. However insignificant when singled out, when grouped together as a swarm, colony or a brain, they can generate astonishing properties. Are the properties of these superorganisms enough to conclude they can think as one, just like the brain? In other words, is there colony-level cognition?

An example of such an emergent property is colony-level decision making exhibited by ants during house hunting. The scout ants visit potential house sites. They collect information about the site, including the size of the cavity, the width of the entrance and the darkness.  If a scout ant evaluates the house to be appropriate, it starts teaching other ants the way to the new house, so they can also evaluate it. This is done by secretion of chemicals called pheromones along the path to the house. The other ants can smell these chemicals, which allow them to trace the correct way. This behaviour is known as tandem running, and enables other ants to visit the site and decide for themselves whether they think it is a good site or not. If a nest is of good quality, a scout will wait less time before recruiting others to it, whereas if it is of poor quality they will wait a lot longer. This period of waiting is the latency period.

House hunting ants
When enough ants are present in the new nest a quorum is reached, and the whole colony makes a decision to move. This is a rapid move whereby ants start carrying other ants on their backs to speed up the process. The quorum threshold depends on individual situations. In times of danger speed is more important than accuracy so the quorum threshold decreases drastically (less ants have to be present in the nest in order for a decision to be reached), whereas when the colony is safe the quorum threshold rises so a more accurate decision can be made.

Just like ants, bees reach the decision of moving their hive collectively. Individual bees go out looking for new hives. When they encounter an appropriate site they do a waggle dance in front of the other bees. The waggle dance informs the other bees about the location of the site. This allows the other bees to investigate the site by themselves. The better the site the longer the bees will dance for. With time more and more bees start to dance advocating their ‘favourite site’. When there is a close match between two sites bees start to ‘buzz’ one another in an attempt to silence the bees advocating the competing site. This allows for a collective, final decision to be made.

Just like ants and bees, neurons ‘make’ decisions collectively. An example of this can be seen when a person is presented with a screen with some dots going right and some left and a decision has to be made as to where most dots are going. Some neurones will be firing due to left dot movement and others due to right movement. Final decision is based upon the larger number of neurones firing for either side.

So there you go! Ants, bees and brains have more in common than you originally might have thought. A lot of research in this area is still going on and we are learning more and more about the fascinating properties of colony-level cognition. Some of the pioneering research in this field is actually being carried out by researches at the University of Bristol. If you would like to know more about the information in this article let us know via email or otherwise, and we will provide you with the references used to write it.

More information:

Waggle Dance of the Honeybee - http://www.youtube.com/watch?v=bFDGPgXtK-U


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