Dungeon bosses should have a minimum quality set to them according to their power just like every animal has. Considering the HP I'm going to guess that q40-50 should be good enough for the ant queen. Not sure if it's a bug or not, I'm gonna assume it's intended: I recently got a q10 ant queen. And yes, everybody that contributed in the fight had their survival at least 200. Many of the mobs had qualities between 20 and 70. They should have started a revolution to overthrow the queen
Anyway, even foxes have a minimum quality of 25 or so without realm buffs. I can understand the varied quality for the lesser dungeon mobs, but considering the rarity of dungeons and how ants have an unusual armor penetration compared to most entities in the game, it makes for a disappointing boss carve after you're done. Especially since its unique items are probably the biggest reward you can get aside from the small heart container.
Another fix would be to increase the chances the dungeon will appear from raiding the ant hills so that you can try your luck more often. But doing that might decrease the value of the heart container so I'm not sure if it's a better alternative.