AAcross many cities, beekeepers have begun to notice that the number of hives is rising even as the countryside loses some of its traditional pollinators. Rooftops and balconies now provide a surprising variety of flowers throughout the year.

BThe change is not simply a matter of putting more insects into an urban landscape. Bees carry pollen between gardens, community plots and parks, connecting small habitats that would otherwise remain isolated. This hidden network can make a measurable difference to the plants that feed a city.

CResearchers are therefore looking beyond honey production. Their surveys compare flowering calendars, pesticide use and the movement of different species through built-up areas. The results suggest that a city can support biodiversity when its spaces are designed as a connected system.