My female is 1 1/2 years old already (how time flies). She REFUSES to eat anything but hornworms. Can she survive on eating only hornworms? has anyone else ever fed only one food item to their beardie and if so, did she live a long life? I know this sounds horrible, but believe me, I have tried starving her for a month and she only wants hornworms.
For a 1-1/2 year old bearded dragon, I think hornworms are pretty healthy. They are lower in fat than crickets, Repti-Worms, and waxworms. They have a great calcium to phosphorous ratio (1:3), too. You do still need to dust them with calcium. The only concern I would have is that they are low in protein, but your dragon isn't growing, so I think a lower protein feeder is fine for an adult. They have 9% protein, compared with Repti-Worms at 9.4% and crickets at 21%.
So if you are interested in their nutritional value, I think they are great.
BUT...I agree with Brandon. A varied diet is best. It can be very stressful to worry if you can't obtain a certain feeder. Then again, you've tried the tough love for a month and she didn't eat anything, right? So if you can't get hornworms for a while, she will just go without or learn to eat something else.
Keep trying other insects because your beardie may just be going through a picky faze. My beardie Grievous went through a 3 month period where he refused to eat anything but crickets but eventually it passed and he is back to eating a variety of foods again.
Hope this helps,
Sadie