There's also the separate evolutionary axis of how the beetle behaves: they learned to seek out termites and collect food from them, exposing themselves to quic

There's also the separate evolutionary axis of how the beetle behaves: they learned to seek out termites and collect food from them, exposing themselves to quick lynching if the disguise fails. It's easy to imagine intermediate states where mediocre disguises work some of the time and the beetle is cautious because it occasionally needs to run away.