Slugs and sweat

Factual Questions
1

“A good reason why slugs may never have become faster movers as a result of evolution is that working up a salty sweat would be ultimately self-destructive for the poor critter.”

That’s a mindless idea that occurred to me as I strolled across the park yesterday, but it did lead me to another, more logical thought:

The routes taken by slugs may be chosen in order to avoid salty terrain (eg, parts of Utah) and sweat (eg, your skin in a hot tent in summer). Is that so? And could they detect it before “treading” on it?

2

Salt in any form is not instantly fatal to slugs - that’s just a common misconception - it’s bad news for them if they encounter crystals of it, but in a natural setting this would just hardly ever happen. They stay in damp places where salt tends to be dilute and not fatal to them. The can be found in quite close proximity to the sea.

I suspect that any scarcity of slugs in Utah (if indeed there is such a condition) would have more to do with climate than salt on the terrain.

3

They occur in the sea as well.
http://www.divegallery.com/morebran.htm