Spectra
Red
A vivid deep, luscious colour which Bumblebee found very pleasing to the optics, though it had the ability to both strike hope and fear into his spark.
Red was the colour of his faction, it showed what they stood for, what they fought for, freedom, peace and hope. The sight of the red autobot insignia was enough to send fear into the sparks of some decepticons. It was a symbol for a future of a free Cybertron, a free Earth, something Bumblebee now more then ever would fight more fiercely for. Not for just his people, but for Sam, his charge deserved to live on a world free from the war of two alien factions, and Bumblebee would do his damndest to make sure that was possible.
Pain and fear, the colour red was sometimes the very last thing an autobot saw, the deep crimson red of a decepticon's optics before their spark was snuffed out of its spark casing. It was the colour of the enemy; many times his charge would come to him in the dead of the night, standing outside of Bumblebee's door. Sam didn't need to say anything, Bumblebee knew. The nightmares, that same flash of crimson that haunted his own waking hours, also haunted Sam in his dreams. It reminded them both what could happen if they stopped fighting.
Red reminded Bumblebee what he stood for, what he was fighting for and what he had to prevent. He had to fight, fight to protect everything that was dear to him, for Earth, for Sam, for Cybertron. The colour red drove Bumblebee forward, so he might one day, be able to live in a world free from war, from hate, but instead, live in a world filled with peace.