Typically (from my reading and viewing) they grow larger, and generally poor soil conditions, hence the need to supplement their food income by enticing insects down into their pitchers to be dissolved and digestedThose are a form of "Pitcher plant" are they not @ewkaw? Though I had no idea they could grow and thrive that small.
No, they are not related to Pitcher plants and are not part of the carnivorous. Just look like that I guess :)
They do attract flies to go inside though as pollinators, but will not "eat" them.