Wasps in hot climates build elongated nests, while in colder areas they tend to be circular. Mathematics cannot explain that, but there are questions about numbers of cells that can be answered.
The College Mathematics Journal © 2003 Mathematical Association of America
Klein JC, Sibley TQ. 2003. Taking the sting out of wasp nests: a dialogue on modeling in mathematical biology. The College Mathematics Journal 34(3): 207-215.