There are indeed only two categories: either we say there's no meaning at all (and at the scale of the universe it definitely looks so) then there's no difference between a human and an ant, we're all nothings. Or, we say there is a meaning in humans, then we must give meaning also to smaller critters like you suggested, just don't look at the scale of the universe :) Or of course, we accept meaning as a very local thing then everybody can redefine their own, even the ants which would surely say "what a meaningless thing is that hooman colony New York".
I believe that meaning is derived by the living organism.
I imagine ants to have a form of OCD where they feel the fear if they don’t do what they are compelled to do.
Humans think they have free will. I don’t think so, we all do what we are compelled to do (and that could just be follow the herd)
