Is paper edible? Technically, yes. Most paper, however, is made from plant pulp, which is made of cellulose, which the human body cannot digest. Termites, on the other hand, can digest cellulose-- they do eat wood, after all.
I always thought termites were closely related to ants, but they're only is the same class (Insecta). Termites are most closely related to cockroaches.