also an alternitive, is meal worms, you can buy one container to easily culture them. if you have some spare tupperware, pour some oats in about two or three, to act as a bedding, they love it and keeps them from stinking up, drop either a potato, carrot or piece of lettuce(carrot reccomended) as well as some empty toilet paper halves. and over time, some(eventually all, some will die off) should grow into a pupi; a sort of cocoon stage for a bit and eventually beetles, soon enough the beetles will mate and produce eggs and the , just make sure you separate the pupi from the rest of the mealworms, so they can grow to be beetles and not be eaten by the other meal worms. the beetles will soon lay their eggs and the cycle will continue.

that's the meal worm approach, also i recommend feeding the mealworms with tweezers, it makes them wiggle around more, giving more incentive for the froggies to bite.