Back home, I dumped the termites into the $10 kid's sandpit we bought as a Polly Pool when it's hot, and placed Rexie on top of the lumps. At first she was nervous and tried to dig through the bottom, but after 15 minutes I could hear her snuffling. She was sticking her nose into the gallery holes and sniffling like mad. I wondered if she was actually eating or only smelling the termites. Occasionally she'd reach up an tear a lump apart with her claws. She pushed her nose into a hole near the top, and I could see through the few layers of holes a long, pink tongue flicking around inside. She was eating! After half an hour she'd finished and curled up. I put her back in the cage.
So I suppose we can call that a success. I'll get more termites tomorrow, and some time in the near future I'll actually drop her on a nest in the bush to see if the dig instinct kicks in.