Yep, so far looks like the best way to get loot from them at a decent rate is to straight out fight them =/ Don't think we will be able to farm them like we can with the other mobs on the surface world.
I'm in the process of building a lava trap that might work somewhat well. Basically it's just a line of thin lava falls that they fly into. Only thing that is going to be tricky is getting them to die from the lava, but not having to loot burn up as well.