An act of cruelty requires intent.
If one intentionally (consciously or not) harms another (human or any other life form) that is cruelty. That includes stepping on an ant IMO.
Sorry thomas, I guess I'm still hung up on these 2 comments. You didn't include an OR statement, they still stand in opposition to each other.
And to remove intent by saying that accidentally stepping on an ant is cruelty, you've just stated that every living creature is cruel and removed any onus from cruelty whatsoever, since I'm sure even the noble elephant will occasionally meander onto an innocent ant colony and unintentionally obliterate it from the face of this cruel earth.
(The lettuce reference was about keeping an organism in a place it might not naturally be or the optimum environment before killing it, and the bacteria reference is about unintentionally killing an organism, even a whole civilization of these organisms, after its use to us is over, although I sometimes participate with great glee :-D)
And for the record....they're called "Italians", "Russians", "European", and "carniolans" because that is the area that they are from. And that isn't near the equator, about the same level on the globe as we are. Feel free to look it up. Fly straight east, and you'll fly over the areas where the majority of our bees originated. I realize that most areas the climate is different somehow, but in many of the areas the climate is just as harsh.
Our bees don't choose where they live, we do, although sometimes we can make it so inhospitable to them that they leave.