I don't remember much of this but studies have been conducted in the USA on human sleep and the patterns have been compared with ant's sleep. I suppose this was done for some beneficial reason for some purpose but I can't for the life of me remember why.
It depends very much on the species but yes, some species sleep for up to 6 hours per day. This is not like human sleep, more like something that could be compared to a daydream in humans. Ants apparently have the largest brain of any insect.
This is not a stupid question at all, in fact it ranks in the top 10% as far as I'm concerned.