Whoops, missed this earlier today. I am still not 100% sold on beetle build for general use, although I do like it on weird maps like WHJ, or weird comps where they have multiple heroes that are heavily reliant on easily-blocked skill shots, like a Stiches/Ming. The build I was using to test him was:
Level 1: Either Nerubian Armor or Regen Master depending on comps.
Level 4: Bed of Barbs or Shed Exoskeleton. I may be weird, but I am a huge fan of the move speed talent on him. I use Bed of Barbs if I need more CC, and it is decent against Valeera because if she moves across the spikes even after they stun, she will be revealed, so I can restrict her movement options with that.
Level 7: Chitinous Plating.
Level 10: Cocoon.
Level 13: Urticating Spines. Now that the tower aggro has been toned down a bit, I like this the best from this tier. It is a more controllable Burning Rage.
Level 16: Epicenter.
Level 20: Rewind.