Direct comparison of alternatives isn’t always the best way to make a decision – at least if you’re an ant. House-hunting rock ants collectively manage to choose the best nest-site without needing to study all their options, according to new research from the University of Bristol.
 
Dr Elva Robinson and colleagues in the Bristol University’s school of Biological Sciences fitted radio-frequency identification tags to the backs of the rock ants (Temnothorax albipennis) which measure up t Read more

Direct comparison of alternatives isn’t always the best way to make a decision – at least if you’re an ant. House-hunting rock ants collectively manage to choose the best nest-site without needing to study all their options, according to new research from the University of Bristol.
 
Dr Elva Robinson and colleagues in the Bristol University’s school of Biological Sciences fitted radio-frequency identification tags to the backs of the rock ants (Temnothorax albipennis) which measure up to 3mm in length. Two thousand of the tiny transponders would fit on to a postage stamp.
 
The scientists then watched the way the ants chose between two nest sites to make their home. The ant colonies showed sophisticated nest-site choice, selecting the superior site even though it was nine times further away than the alternative.  The best nest was chosen, despite the fact that very few individual ants made direct comparisons between the nest-sites. Radio tagging was used to monitor the activity of the individual ants in the colony by fitting a tiny transmitter to the back of the ant, this was a challenge in itself given that the tags are just half an millimetre in diameter.
 
In the Bristol tests, very few ants appeared to make direct comparisons between the two nests by making multiple visits to each before choosing one or the other.  However, approximately half (forty-one per cent) of the ants that first visited the near nest later switched to the far nest, whereas only a tiny minority (three per cent) of the ants that first visited the far nest switched to the near nest.  This ultimately resulted in the entire colony ending up in the better nest. Her study showed that ants are great house-hunters, perhaps more so than humans! This study could have wider reaching significance, particularly in computing where computer algorithms are designed for modelling collective decision making. Close