As to your question : nope.
Can you play in a humans only world? Yep.
Can you play in a world where evryone plays insects? sure, whatever makes you tick (mmh gotta remember this idea)
But something very similar is. By definition, it's not possible to coherently roleplay something totally alien. That's why so many races are just humans with a few physical changes. Short humans. Stout humans. Tall humans. Blue humans. Aquatic humans. Flying humans. Celestial/infernal humans. And so on.
Hmmm...For some reason the poll didn't show up when I first viewed the thread.
Regardless, my point is that it's not possible to play a truly non-human mindset. It would be like playing a world where all the physical laws are different. No matter how hard we try, we would perceive that world through a filter of our own. The same with creatures - that one attacks because it's hungry, or it's angry, or it's territorial, or it's frightented, etc. How do we actually know what an animal thinks? We don't - we view it's behavior and fit it into a framework we can understand.
I suspect my response is a bit off-center from your real question though, which seems to be - do we specifically have to have "human" available as a racial option in an rpg? I'd still say no, but there would have to be a very compelling reason for that option to be missing.
I've played a couple of times in No Humans games, but realistically, it just ends up as Humans-with-different-faces-and-maybe-a-quirk, sorta like Klingons in Star Trek.
I might or might not play in such a game again, dependent entirely on who is running the game, rather than what the specific game world might be.
While not essential, it's hard to vcome up with races that are well defined and easy for people to play. Most of the times it just seems like races become cliches very fast.