Before revision:  We consider two types of pheromone fields: one emanating from the nest, and other actively produced by ants in their nest bound journey after finding a food source.
After revision:  The individual model takes the form of a Langevin system of equations in polar coordinates driven by two-dimensional Gaussian fluctuations and with orientation changes in response to two pheromone fields: one emanating from the nest, and other actively produced by ants in their nest bound journey after finding a food source.