As a 61 warlock it was pretty straightforward to solo grind my way to Natalia.  The main problem was figuring out which tunnel system she was in since that hive has 3 and I couldn't seem to find the right entrance.  (It's the tunnel entrance in the far south of the hive.)

I cleared the room with Natalia by single-pulling bugs into the adjoining hallway.  Then I opened on Natalia with Fear and loaded her with DOTs. 

As the fight progressed it was clear I would be able to finish her off before I ran out of mana or health.  She was perhaps down to 50% when a bug repopped.  This was the neutral bug that stands near Natalia.  It had been the last bug in the room to die and I had killed it less than 30 seconds before attacking Natalia.  The bug aggroed immediately upon respawning.  Game over.