The Bugs are equally as intelligent as human beings. Except their instincts are different. They have developed laser beam guns, missile weaponry, advanced spacecraft, planet colonisation, and other advanced technology. They bring rifles into battle and shoot back. They are not the giant, savage animals of the movies. However in the book, the military propaganda pushes to its soldiers that they are stupid, savage animals who need to die. In fact, this difference is stressed: "...stupid races don't build spaceships".
It is not explained if their technology is mechanic or organic, like the Plasma Bug (living artillery) in the film universe and the Transport Bug (bioship) in the television series Roughnecks: Starship Troopers Chronicles. Yet, it is most likely them using mineral elements like iron or aluminium, and the shells of dead insects to build their tools. The brain bug in the novel shows a mixture of natural and technological elements in their faces. They may actually be cyborgs, with computer and satellite tech implanted into their bodies so they can become a brain bug. Whether this just makes them better brain bugs, or whether they only become brain bugs due to cybernetics, is unknown.
Arachnid society is based on a caste system like ants and termites. They do this so to coexist prosperously, as in both the films and the books. However, in the novel, the difference between the workers and warriors is that the workers are pacifists who will run and hide, and warriors are those who will pick up their guns, rush into battle, and kill. Warriors can not feel fear or be intimidated, while workers can. It is theorised they do not have emotions — at least of the human sort — and they never retreat unless they know they can't win. The individuals of the lower castes, such as Warriors, are telepathically connected to the Brain Bugs. The Bugs won't hesitate to kill their own kind of any caste should the situation demand it; they are ready to expend thousands of Workers in a diversionary action, or to wipe out their ruling castes to prevent their capture.
Death has little meaning to an individual Bug. Combined with the large numbers of Warriors, they are able to breed, they favor large swarm tactics, and human-wave attacks (or "Bug-wave" attacks) to overwhelm their enemies. At one point in the book, a Mobile Infantry trooper notes that "they expend Warriors like we expend ammunition".
They are described as looking like "a madman's conception of a giant, intelligent spider." They are said to have a somewhat human-like torso, and use a pair of hands to field their guns. Also, the Bugs can see into the infrared spectrum: though pitch dark to human eyes, the underground corridors of a Bug colony are well-lit when viewed through the infrared "snoopers" of the Mobile Infantry's Marauder Suits.
- The Psuedo-Arachnids are also referred to as "Arachnids" in the Starship Troopers table-top wargame.
- They are called "Archies" by the human soldiers, which is based on the derogatory names "Jerry" for Germans, mixed with "Charlie" for Vietnamese.
- In the movie Starship Troopers, the production and director said they did not want the arachnids to be smart or use weapons, but instead wanted to make them ruthless animals. The arachnids were given a striking color scheme and made to look more brutal, bigger, and vicious.
- The pseudo-arachnids may be based on the real life jumping spiders, as these little spiders have big heads, two large and intelligent looking eyes, and are one of the most intelligent invertebrates on Earth. The rest of them are based on termites and ants.
Outside Starship Troopers franchise
- The movie Aliens features concepts inspired by the novel Starship Troopers. The actors had to read the novel to prepare for the movie.
- The Tyranids from Warhammer 40,000 are based on the pseudo-arachnids, and xenomorphs from the film Aliens. Both of which came out around 20 years after Heinlein's book was published. Not surprisingly, the space marines of Warhammer 40,000 are inspired by the power armor wearing troopers of Starship Troopers as well. (The Imperium of Man is inspired by the Imperium of the Dune novels and the real world Holy Roman Empire.
- The tabletop wargame also produced models that use the original novel description of the arachnids, called "Spider Bugs."
- The tabletop game 'Alien War' by Defiance Games is based on the Starship Troopers novel, and the Hudson Bugs in the game are almost directly drawn from the novel pseudo-arachnids. The difference is they are given mantis arms instead of a pair of arms with hands.
- The "ants" in Armor by John Steakley are actually a less conservative and more liberal look at the pseudo-arachnids, and the entire Starship Troopers world.
- A race called "Arachnids" and depicted in a very similar way than Heinlein's Pseudo-Arachnids is introduced in the tenth volume of the Japanese light novel series Gate.