I would suggest pinhead crickets if you are looking for a supplement. The easiest thing to do is get a small batch (20 or so) of adult crickets and put a small dish with moist soil in with them. In a few days, they will lay thousands of eggs. You can then rotate another laying dish in. Depending on temperature, the eggs will hatch in one to three weeks.
Some people keep a colony of adult crickets going, but if you are not feeding lots of animals it might make more sense just to get a new batch of adults at the local pet store when your breeders die off. The pinheads will eat just about anything, just make sure they have moisture. Also keep in mind that in a week or two they may be too big for your frogs! Cooler temperatures will slow their growth considerably.
This is actually a fairly cheap and easy way to provide some variety to your frogs. There are some people who simply place the dish in the terrarium and let the frogs eat as the pinheads emerge, but I would not recommend this as it is too easy to get a swarm which is more than the frogs can consume.
As for termites, most are a "colony" type animal, meaning there would have to be a queen to infeset a house.