For this week’s SUMS talk we are lucky to have Mary Myerscough as speaker. Abstract: Social insects - ants, bees, termites and wasps - live in colonies of thousands, sometimes millions, of simple individual insects that interact in basic ways, but together they form a colony that is capable of finely tuned, sophisticated behaviour. Maths provides powerful tools to explore the links between simple individuals and complex, self-organising colonies. I will show how collaboration between mathematics and experimental science has enabled us to unpick how bees can make an accurate communal decision about choosing a new nest site, even though each bee has only visited one potential new home. The maths ranges from slightly bodgy linear algebra, through stochastic processes and ODEs to frank computer modelling.