Just encountered the same issue when trying to harvest Titanomyrma corpses

they might be too small for it to hit them... I'll see about that when I can.

It's not that, when I attack the corpse it makes that hit sound just the corpses don't get harvested.

same happens when trying to mine a titanonyrma or similar with a pick or hatchet, the sound plays, it may even throw a blood decal out, but nothing it harvested and the corpse's still there.
the hit box for them is about a pixel in size after all.

I don't have that issue, each ant or dragonfly I've been able to harvest with any tool or any other dino/creature besides the toxic dragon.

hmm, must be me then, I get the no harvesting thing whenever I try to get something smaller than a dodo...

I'll see about testing it with a toxic next time I work in kit.

^^ I for one also have problems with pickaxe etc trying to harvest Titanonyrma or smaller. have to keep trying from different angles lol