And in doing so – discovered something amazing. 

Bumblebee's Cybertronian name isn't Bumblebee.

It's just Bumble.

We know this isn't a character limit thing, because Bulkhead's name is written out in full. 

Which means the 'Bee suffix was added after coming to Earth.

And now I'm imagining shortly after the original four's arrival, Bumble doing recon on humans, as would be his scoutly duty to do so, and seeing them flee and flinch warily from tiny, yellow and black creatures, even when it's just one. He brought it up to Ratchet, who then took it upon himself to research it (cursing and grumbling at human tech the entire way), and informing him about all of the small insects that come under the common reference of bees. One of these that he mentions, is of course bumblebees. Upon hearing that, Bumble – already attracted to these little yellow and black creatures that strike terror into the hearts of things much, much bigger than them for fear of their sting – excitedly asks everyone to start calling him Bumblebee.