I had no idea mealworms were that high in fat. I "assumed" crickets were actually higher. My bad. I think the probelm with mealies for animals is they gulp them down w/o killing them, and they can do some internal damage that way.
No doubt on the waxies for being fatty. Are red worms ..like the small type of earth worm? That might work in a Nep, but even a tiny chunk does really bad in a VFT. Rots the trap. I would think a earth worm would be worse than a waxie.