Most people will want some sort of netting when there's moderate to heavy pressure from biting insects. I carry a three ounce mosquito net in these situations. A full tent is not required.

Insect repellent and site selection (don't sleep next to lake) handle low bug pressure situations.

I don't worry about other critters where I hike in the PNW.

How light do you get your pack (minus the starting liquids).

Some people get down to six pounds. See https://www.youtube.com/watch?v=LHmtdtctzzc and https://www.youtube.com/watch?v=LggWPhMv-H4.

Depends where you are and the season - bugs are less of a concern in the winter, and harmful spiders/scorpions aren't present everywhere. Plus, a can of insect repellent is still much lighter than a tent