I am asking out of curiosity. I think my phone may be stolen but I can't find it. I am wondering if a thief erased/wiped the phone would it "remove" itself as a listing on my Google+ account?
If the stolen device is wiped, then your phone will disconnect from your Google account and you will not be able to locate it. It will stay as an entry on Android Device Manager, but you will not be able to locate or access it in any way.
If you believe your phone has been stolen, you should contact your carrier immediately as they have your IMEI on record and can try to locate it. If that doesn't help, try looking on local Craigslist or eBay listings.