Two extraterrestrial civilizations are also depicted. The "Pseudo-Arachnids" or "Bugs" are shown as communal beings originating from the planet of Klendathu. They have multiple castes; workers, warriors, brains, and queens, similar to ants and termites. The warriors are the only ones who fight, and are unable to surrender in battle. It is also implied that the Bugs are technologically advanced, possessing technologies like spaceships. The "Skinnies" are depicted as less communal than the Arachnids but more so than human beings. The events of the novel take place during an interstellar war between the Terran Federation and the Arachnids. At the beginning of the story, Earth is not at war, but war has been declared by the time Rico has completed his training. The Skinnies are initially allies of the Pseudo-Arachnids, but switch to being allies of the humans midway through the novel. Faster-than-light travel exists in this future: spacecraft operate under the "Cherenkov drive", and can travel "Sol to Capella, forty-six lightyears, in under six weeks".