treats options for red eyed tree frog?

[MissFroggyToes]

i have two less than a year old retf's and their main diet is crickets. i wanted to feed them more of a variety, what else do they like for treats or other food options?
they didnt really like the meal worms, i tried the flightless fruit flys and they didnt even touch them. anything else to fill their cute froggie bellies? :3