Besides leaving their chow in there all day every day, how often are you supposed to feed fruits and veggies? I put in a good handful of shredded carrots once a day and they are gone in an hour or two.
I always have some sort of fresh fruit/veggy available at all times. As soon as the fruit/veggy starts to go bad, I remove it and replace it with something else.
I feed bananas (which dubia seem to love) apples, carrots, greens, squash---most of which I put into the food processor prior to feeding.
My dubia love bananas too. They don't eat the veggies as well, but carrots are sweeter so they will eat those. I put fruits and veggies in about 3 days a week. Fruits and veggies help with moisture/hydration too. You should remove any uneaten fruits/veggies after a day or two so you don't get mold because this will kill them.