I've been struggling with flies for the past few weeks, scratching around each day wondering what on earth I'm going to feed the frogs. hydei culture after culture I set up went bad (liquid, stinking, no flies). I've had to order hatchling crickets each week. At the same time, the melanogaster cultures were doing OK, better than my normal hatch rate actually. Well, I've sussed the problem - temperature. At 70F, the melanogaster do well, but the hydei fail completely. I've had to install a heat mat and a thermostat in my fly cupboard. At 77F, the hydei cultures explode but melanogaster production is down. At 74-75F, I can get both going. Frogs have had breakfast and are happier now!