Web Collaboration, of Sorts
As the number of occupants grows, the volume of the webs they construct increases - but the surface-area-to-volume ratio declines. The area of web is the all-important determinant of numbers of prey caught, so bigger colonies catch proportionally fewer prey items.
Reminds me of Dunbar's Number, the theory that says that groups of larger than approximately 150 people are no longer optimal because humans cannot effectively have and maintain that many social relationships.
Spider Webs Article