Bug (Starship Troopers)
The Bugs are an extraterrestrial race in the novel Starship Troopers by Robert A. Heinlein, its film adaptation (and its first and second sequels, an animated film, a Japanese OVA and loose spin-off television series), sometimes also referred to as the Arachnids, although the aliens are not related to Earth arachnids.
The Bugs in the film differ considerably from those in the novel, which calls the Bugs "Pseudo-Arachnids". The Bugs in the book are an industrial society that builds starships; the film Bugs have no technology, only specialized castes including "plasma Bugs" that can fire burning fireballs into orbit. Meanwhile, Mongoose Publishing's Starship Troopers: The Miniatures Game refers to them as the Arachnid Empire or the Bug Empire. In the third film in the franchise, the bugs are referred to as "Archie", similar to nicknames given to Germans ("Jerry") and the Viet Cong ("Charlie") in their respective wars. The novel's Bugs are highly susceptible to radiation and chemical attacks, and the Mobile Infantry frequently seals their escape holes.
Colonization
In the films, the Arachnid Quarantine Zone consists of many star systems colonized by the Arachnids. At some point "plasma" bugs developed the ability to fire spores into orbit, and so colonize other planets.
In the first film, Klendathu, Tango Urilla, and Planet P are the only worlds explicitly shown to be colonized by Arachnids, although an unspecified number of planets are under their control. It is also shown that they slaughtered a colony of "Mormon extremists" on a planet called Dantana. In the TV show, multiple celestial bodies, including Pluto and fictional planets, are inhabited by the Bugs.