Buddhists are not all the same. Not by any means! So what one Buddhist did about pests, vermin, etc, might differ greatly from what another one did.

You can't organize life rigidly around a set of prearranged rules (unless you're a bit crazy...), you have to deal with each unique situation in the most suitable fashion.

I don't find household pests to normally be a very big problem. Having simple things like screens can keep most of them out, but when I'm in Trinidad or Cuba, for example, there usually are no screens. Accordingly, a lot of mosquitoes can get in at night through the various windows, which are not sealed as they would be in northern climates. In a situation like that you either lose a whole lot of sleep every night and go crazy swatting mosquitoes in the dark....or...you calm down and accept the fact that you are going to get some bites and learn to sleep regardless. In time, you hardly notice them. You also have to learn not to scratch the bites you get (and then they stop itching within a few minutes and vanish). This takes some resignation and self-control.

If I had a house of my own down there, however, I would no doubt get screens!

As for ants, well, you usually have to remove whatever food is attracting them to some other place where they can't easily find it. Then they go elsewhere.

Spiders and hornets in the house? You can catch them pretty easily and put them outside, by using some tissue paper, a glass, etc...that's what I tend to do. They're happier outside anyway.

Why kill things unnecessarily when there are other simple solutions?

I think people usually kill bugs because they are scared of them. It's a fear-based reaction. That's why hornets sting too. They're afraid. When you try to kill them they naturally get more afraid, so you had better get it right the first time!

I think some people spend far more time worrying about stuff like this than is really sensible. It's not that big a deal. Nature is full of bugs. Live with it. Your ancestors did, after all. Bugs are interesting. Learn to enjoy observing them and you'll get to like them better (with the probable exception of mosquitos and other little biters!).