Many years ago I spent a lot of time in spike camps in the Sierra and the mountains of Nevada cowboy camping, occasionally under a tarp. I had a few incidents with scorpions, but luckily wasn't bitten. In case you Sierra buffs wonder where there's scorpions, it was at about 7,000 feet elevation above Olancha. Both my wife and I have been bitten by spiders on separate occasions, as we experimented with tarps as we've gotten older and weight conscious. The worst tarp side -effects have been wind driven dust, rain and snow. If I mention tarp to my wife she starts getting that look.... We just bought a very comfortable tent that fits 2, all our gear, and still has space, and is under 2 1/2 lbs. with stakes and groundcloth included. I can roll up the doors on my tent and stargaze very well in any direction, yet it buttons up tight when needed. Tarp? It's what I cover my lumber piles and tools with.