I personally don't treat my quails with mealworms for a couple of reasons.
One, they're quite expensive and I have a lot of quail.
Two, mealworms look a lot like quail toes. I've heard this can encourage pecking toes, and as I already have a toe-pecking male who always pecks his chicks, I've avoided mealworms.
Three, When I did feed mealworms once, it turned my quails nasty. I have a cage with king quail females, a mother and her adult daughters she raised who always got along so well and were inseparable. I thought since they weren't my breeders and I had some mealworms from feeding my japanese quails (they would attack me for them so I stopped), I would give my lovely girls some mealworms to treat them. THEY WENT INTO AN ALL OUT FRENZY!!! Even the mother started attacking her daughters and looking around for more. I've found they haven't gotten along the same since.
That's just my experience, plenty of other people do it with no problems and they do love them. I have fed my quails crickets which they love to chase and feed to their mates and chicks, but without turning them into little monsters ha ha. I will probably get some more crickets soon and give them some every so often. Good luck.