DeathWraith,
Xenomorph,
10 years ago
Nice, gonna edit this post with all the details.
Life Cycle
(Chestburster ----> Drone ---->) Queen Egg ----> Superfacehugger ----> Queen Chestburster ----> Queen ----> Egg ----> Facehugger ----> Chestburster ----> Drone ----> Warrior (----> Praetorian)
I go here for a chicken-before-the-egg theory because I assume that the first fully developed Alien came from someone's chest, not from an egg. I can't assume that it was a traditional chestburster that burst out of that poor creature's chest, but I assume that it grew into a drone that we know as the Giger Drone. At the same time, I want to believe that Praetorians are a possible development beyond the warrior stage, which occurs when a hive has grown enough that it has some to spare.
The Queen egg, due to its capital importance in preserving the species, can come from a few different sources: it can be constructed by a drone or a warrior through the slow process of morphing another living being into an egg, or cam be laid by the Queen. This usually happens when there is no Queen in the hive or when the Queen believes herself to be in mortal danger.
This egg will result in a Superfacehugger that can impregnate at least one organism with a queen embryo and one organism with a regular embryo. The Superfacehugger is larger and much darker in colour than the regular facehugger.
The Queen is usually stationary and laying eggs in the central room of the hive, attached to a fixed appendix with a moving end that holds the eggs until they mature and then places them in an empty spot. It is unclear whether this appendix is part of the queen at all, or a separate organism, just as it is not clear whether the Queen is a hermaphrodite, or the hive itself is an organism that provides the male part of the reproduction process, but given that a queen can lay eggs while apart from the hive, being a hermaphrodite is more likely making it the only member of the Xenomorph species that is not asexual. The queen can detach itself from this appendix with seemingly no damage to either side.
The chestburster is sort of a pupal stage. It has a relatively small, worm-like body and underdeveloped limbs, so it moves around by slithering. It will try to hide and grow into a drone. Xenomorphs do not need to eat, as an animal would, in order to grow or stay alive. The process through which they feed is still unknown, but given that most of their body is silicone based, eating things like humans or human food would not help them grow much anyway. Xenomorphs also do not need to breathe in order to stay alive, being able to survive in vacuum, though they may need to breathe in order to effectively live - that is to move and think - and go into a dormant state when deprived of air.
Drones and warriors are similar stages. A warrior is just an older drone that will most likely appear once the hive is well established. Drones will most likely be seen on their own because of a lack of a Queen anywhere nearby, meaning that they are specialized in establishing a hive. Once the hive has a Queen and enough drones, they will grow into warriors and specialize in killing enemies rather than retrieving victims, which ironically makes them less efficient.
While developing inside a host's body, the Xenomorph will take some of the host's genetical features, but this will not lead to a major difference in purpose or physiological capabilities: for example the dogalien/runner is better suited for quadrupedal locomotion and the predalien has a yautja style set of jaws, but they are still regular drones or warriors with the same role of drones or warriors born from humans.
Drones have a very large brain, larger than any other known living creature, giving them a potential intelligence well beyond that of humans. A Xenomorph only hours old is able to understand complex machinery on first contact and predict the behaviors of enemy creatures after short observation. This potential, however, is thwarted by the extremely powerful instincts that drive them to establish hives and live as highly intelligent insects.