That's because giant centipedes are rude!
Haha, indeed... renowned for disrespecting guests at parties. :)The fire beetle on the other hand is a most gracious host, and is known to provide homely meals to all visitors. Their conversation technique is somewhat lacking however.
Like the fire beetle always says "click click tik tik squick tik tik" with a charismatic sly look!
I think it's the way they glow, sort of reminds you of a camp fire. :)
Sounds like a Type III-ism. IIRC, having a Charisma score means that the creature is self-aware.