Social insects on TV

At last I caught up with BBC's Life in the Undergrowth programme on social insects. Marvellous! Along with a segment on giant Asiatic honeybees (watch here) was a feature on Arizonan ants: by day harvester ants search for seeds, but before retiring for the night roll stones over the nest entrances of night ants to delay their night-time search for the same scarce foodstuff. Oh, what wags!