Before the Xenomorph is ever shown in Alien, the audience is introduced to tiny traces of what appears to be something larger going on. Tiny, subtle clues like the space jockey, and then the eggs, and then John Hurt's exploding stomach.
20th Century Fox
Like the Xenomorphs, the termites left behind just enough evidence to let me know something wasn't quite right, but it was never enough to set me to action, which is weird because the evidence was poop. They shit everywhere, and their shit piles up into little mounds that usually look like coffee grounds or pepper. I've never had the pleasure of really getting my face near their shit piles to examine their turd pellets closely, but apparently termite poop is six-sided. Every time they take a dump, termites drop weird D&D dice from their assholes like they're rolling for damage against my front door.
Finding piles of shit lying around is a good indicator that something has gone awry in pretty much any scenario. If you found a mound of shit in your cubicle at work, you'd ask HR if it meant anything about your employment status, for example. But, as with the start of any movie about aliens (and any kind of movie monster in general), the first sign of trouble is usually ignored; it's rationalized away as nothing. Probably because acknowledging there is a problem at all means having to deal with it and spend money on it. I'd rather my apartment fill to the ceiling with hexagonal turds than have to do things. My life is a spectacular quest to avoid hassle.
"WHAT? A PROBLEM? NO. I DON'T SEE ONE ANYWHERE."