I think I found the answer myself. From As has been suggested, the Xenomorph life cycle is loosely based on the life cycles of parasitoid insects.
From the excellent site Strange Shapes (which is the translation of the word "Xenomorph"):
When Dan O’Bannon started conceptualising his alien creature he turned to two key influences: the creatures depicted in the comic books he devoured as a child, and the insect world. “Works of fiction weren’t my only sources,” he explained in his essay Something Perfectly Disgusting. “I also patterned the Alien’s life cycle on real-life parasites … Parasitic wasps treat caterpillars in an altogether revolting manner, the study of which I commend to anyone who is tired of having good dreams.”...
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**The insect world, O’Bannon knew, was one of sheer brutality, where even acts of copulation routinely result in murder++
The insect world, O’Bannon knew, was one of sheer brutality, where even acts of copulation routinely result in murder. Indeed, certain parent insects quickly become fodder for their newly hatched spawn (an anecdote about a spider being eaten by its children is used to disturbing effect in Blade Runner.) Insects..Insects are also notoriously cruel to other species of insect – the relationship between flies and spiders is an obvious horror, but varieties of wasp also use the bodies of other insects as the host for their young. A genus of the Phoridae fly, the Pseudacteon, also known as the ant decapitating fly, is infamous for its violent use of ant bodies: eggs are laid in the ant’s thorax, and the larvae migrates to the brain, where it feeds on the hemolymph and muscle and nerve tissue. “After about two to four weeks, they cause the ant’s head to fall off by releasing an enzyme that dissolves the membrane attaching the ant’s head to its body. The fly pupates in the detached head capsule, requiring a further two weeks before emerging.”
Ridley Scott added: “There’s a fundamental connection in nature because we actually watched, in preparation for this [movie], Oxford Scientific, [which] had this interesting piece of footage where they’d watched a slice of bark, and there’s a grub underneath the bark … Across the top of the bark was this insect, which passes over the grub, stops, backs up, and ‘feels’ the grub is there, let’s say, the equivalent of 8 feet below you. It goes up on its hind legs, produces a needle from between its legs, and drills through the bark and bulls-eyes right into the grub and lays its seed, so that the grub becomes the host of the insect.”
At first, O’Bannon was stuck on the point of getting the Alien on board the spaceship. Having it simply sneak aboard seemed too banal. But if the creature could stow away within the body of a space-man… Dan, fascinated and repulsed by the horrific life cycle of parasitoid wasps, incorporated the concept into his alien monster. It would gestate inside a living host and explode from their body. The Alien could get on the ship, and excitingly, not without spilling blood.Ridley Scott added: “There’s a fundamental connection in nature because we actually watched, in preparation for this [movie], Oxford Scientific, [which] had this interesting piece of footage where they’d watched a slice of bark, and there’s a grub underneath the bark … Across the top of the bark was this insect, which passes over the grub, stops, backs up, and ‘feels’ the grub is there, let’s say, the equivalent of 8 feet below you. It goes up on its hind legs, produces a needle from between its legs, and drills through the bark and bulls-eyes right into the grub and lays its seed, so that the grub becomes the host of the insect.”
At first, O’Bannon was stuck on the point of getting the Alien on board the spaceship. Having it simply sneak aboard seemed too banal. But if the creature could stow away within the body of a space-man… Dan, fascinated and repulsed by the horrific life cycle of parasitoid wasps, incorporated the concept into his alien monster. It would gestate inside a living host and explode from their body. The Alien could get on the ship, and excitingly, not without spilling blood.
“The Alien franchise bases its Xenomorph life cycle on parasitic wasps on Earth,”“The Alien franchise bases its Xenomorph life cycle on parasitic wasps on Earth,” Terry Johnson, a bio-engineering researcher at the University of California, told Popular Mechanics. “It’s a pleasure to see a film that acknowledges just how weird life can be.” But despite the blatant insectile nature of the Alien (specifically its four-staged life cycle and cocooning) and despite O’Bannon, Ron Cobb, Ron Shusett, HR Giger, and Ridley Scott being clear on the issueO’Bannon, Ron Cobb, Ron Shusett, HR Giger, and Ridley Scott being clear on the issue, fans have been reluctant to admit the insect influence on the original creature, instead brushing it off as an addition made by James Cameron in the 1986 sequel. However, in light of the evidence pointing to the original Alien makers being heavily and happily influenced by insects, attributing this to Cameron is akin to blaming wet streets for rain.
The connection between the Alien and insect reproductive cycles was so crucial that O’Bannon identified it as of “core psychological significance” before quoting biology and science journalist Carl Zimmer: “when an alien bursts out of a movie actor’s chest … it is nature itself that is bursting through, and it terrifies us.”The connection between the Alien and insect reproductive cycles was so crucial that O’Bannon identified it as of “core psychological significance” before quoting biology and science journalist Carl Zimmer: “when an alien bursts out of a movie actor’s chest … it is nature itself that is bursting through, and it terrifies us.”
“I modelled [the Alien] after microscopic parasites that moved from one animal to the next and have complex life-cycles,” Dan explained. “I just enlarged the parasite.“I modelled [the Alien] after microscopic parasites that moved from one animal to the next and have complex life-cycles,” Dan explained. “I just enlarged the parasite. I was interested in the biology of aliens, so I wasn’t interested in streamlining the thing below interest level just for the sake of economy.” Ron Shusett, Alien‘s executive producer and friend to O’Bannon, told Cinefantastique: “It was our idea that it would be the life cycle of an insect. The way a wasp will sting a spider, paralyse it, and lay its eggs in the spider … that we did want it to be …. We thought people might pick up on it and say, ‘yeah, an alien life cycle can be an insect life cycle.'”“It was our idea that it would be the life cycle of an insect. The way a wasp will sting a spider, paralyse it, and lay its eggs in the spider … that we did want it to be …. We thought people might pick up on it and say, ‘yeah, an alien life cycle can be an insect life cycle.'”
Alien and Aliens conceptual artist Ron Cobb further explained the origins of the chestburster scene: “He got that from the paralysing wasp … it paralyses the spider and lays its eggs on the spider, then buries it in the ground so that the living spider serves as food for the wasp larva and you know, he always was so horrified at that idea.”the origins of the chestburster scene: “He got that from the paralysing wasp … it paralyses the spider and lays its eggs on the spider, then buries it in the ground so that the living spider serves as food for the wasp larva and you know, he always was so horrified at that idea.”
In the 1999 DVD commentary, Ridley Scott explains: “The whole notion of this [creature] was taken off a certain kind of insect that will find a host, lay its eggs, and then in that host it will bury its eggs, and then of course the eggs will grow and consume the host.In the 1999 DVD commentary, Ridley Scott explains: “The whole notion of this [creature] was taken off a certain kind of insect that will find a host, lay its eggs, and then in that host it will bury its eggs, and then of course the eggs will grow and consume the host. So that’s the logic of it all. Probably what makes a lot of nature go around.”
“I wanted him [the Alien] to be insect-like. Like an ant.“I wanted him [the Alien] to be insect-like. Like an ant. Because if you examine an ant under a microscope they’re kind of elegant, and I wanted him to be very elegant and dangerous.”
“We decided to make a very elegant creature: quick, and like an insectlike an insect.”
Many fans find the comparison to insects to be demeaning, probably because the words “bug” and “insect” are often used as pejorative terms. But the insect world is one of complete brutality and wondrous, if not terrible, feats of strength and will and ingenuity. Murder, theft, displacement, and slavery is routine. Regicide is often simply a matter of succession. Like Mankind, ants are known to mobilise armies in order to annihilate rivals, a behaviour not even in the realm of our ape cousins, who in comparison engage in turf war rather than full-scale organised and destructive aggression.
It’s not that the insect world is a disordered one -creatures such as ants live in incredibly complex social systems- but that it is an amoral one, where even acts of reproduction require the painful death of a mate or parent insect. Praying Mantis’ devour their mates from the head down mid-coitus; pseudacteon flies lay larva which feed on a host’s brain before they decapitate and erupt from their heads; and botflies turn living bodies (animal and human) into colonies of larvae.
Sex and insects weren’t new to fiction when represented in Alien, with the topic matter going as far back as the English metaphysical poet John Donne’s The Flea, published in 1633. Donne’s poem is narrated by a young man who watches as a fly suckles at his flesh, then moves to feed on a woman he desires. The poet’s language is very sexual throughout, and he notes: “Me it suck’d first, and now sucks thee, and in this flea our two bloods mingled be.” The insect has brought the two together, and the two are now also part of the insect, the creature’s innards now their “marriage bed … cloysterd in these living walls of jet.”
Where Donne’s poem was somewhat comical as well as sexual, O’Bannon’s Alien would focus not on sexual love, but rape, and not on bonding via the transmission of fluids, but on parasitism, all derived from the horrors of the insect world.
“[The Alien’s acid blood] reminded [Dan] of these ants that spray jets of acid to combat enemy ants … At the time of Alien, he had to consult books, watch documentaries, and it took time, but today you just have to explore the web for videos or amazing photographs that make you exclaim, ‘but who designed this?’ before you remember that it is the work of Nature.”
~ Ridley Scott, L’Ecran Fantastique, 2012.
And, as O’Bannon attests, horror abounds in insect circles. At roughly 1700x bigger, it’s easy for a human being to miss the potency and lethality of an ant. Relative to their size, ant muscles are bigger than those of humans, which enables the creatures to lift objects up to fifty times their own weight.
Driver ants, also known as army ants, live on the move, only stopping to establish temporary colonies formed entirely out of their own bodies, much like the nest structures seen in Aliens as well as in Alien’s deleted material. The ants link together using their mandibles, as well as spines and hooks attached to their limbs. These living nests are called bivouacs, can shelter a queen, and come complete with walls and tunnels. When it’s time to move on, the nomadic army ants dissemble and become marching columns that swallow anything in their path, often killing literally thousands of other creatures in a single day, from other insects and spiders, to birds and other large mammals. The ants’ mandibles are solely for killing, crushing, cutting, maiming, and dismembering, as the creatures are only capable of swallowing liquids.
“Gordon Carrol and I talked about this many times,” Ridley Scott explained, “You know, should we indicate the Alien has intelligence? Or great intelligence? Or is it just a time bomb, is it just a war machine? Are those eggs simply war machines? … Ants have, I think, no sense of beginning or end. They just are born, run around doing this thing like everybody else in the community, and die. And I think that may have been the Alien. So, maybe the Alien had no intelligence except pure intuition about survival. Right?”
The Alien can be more accurately described as a protolean being, defined by Wikipedia as
creatures creatures “that begin the growing phase of their lives as parasites, and in particular, typically as internal parasites. As a rule they end that phase of their lives parasitoidally by killing or consuming the host, and then they emerge as free-living adults.”
All of these elements bar the cocooning were present in the theatrical release of Alien. We see the Alien progress through the various stages of its life, getting a glimpse of some shedded skin along the way and even hints of the creature’s limited lifespan – “I wanted a sense of a timeless, slightly decaying creature that, maybe, only has a limited life cycle of, maybe, four days like an insect,” said Ridley Scott, adding: “the Alien lifeform lived to reproduce … [Ripley] killed it, but it would have died soon anyway. It’s like a butterfly“I wanted a sense of a timeless, slightly decaying creature that, maybe, only has a limited life cycle of, maybe, four days like an insect,” said Ridley Scott, adding: “the Alien lifeform lived to reproduce … [Ripley] killed it, but it would have died soon anyway. It’s like a butterfly.”
-The Alien Queen: The Alien society within the hive consists of adult Aliens and their mother, the Queen. Unlike ants or termites, the Alien Queen does not have a need for a male counterpart (ants employ drones, and termites have kings to impregnate the queen). Like the creature in Alien, the Queen is ambi-sextrous, a hermaphrodite, capable of reproducing without the seed of a male. “There are insects like that [androgynous, asexual]” Ridley Scott said of his Alien, “so we based that on a little bit of good old Mother Nature.” The original creature was at first envisioned as a female, before becoming thought of as a hermaphrodite by Scott once Bolaji Badejo was cast (initial efforts to cast a tall, thin woman failed). The Queen likely carries a feminine title (just as the first Alien was dubbed “Kane’s Son”) for clarity and because we tend to struggle without gender-specific labels (though it should be noted that Cameron referred to the Aliens in a male/female capacity – though he also noted that they can change gender if a Queen is present or absent).
It’s usually thought that the insect elements began and ended with Cameron, but in fact not only did they begin with Dan O’Bannon, but they were continued and pursued even by David Fincher for Alien 3. The parasitism and Queen (or an embryo, at least) returned from previous installments, but the third film’s Alien seemed to have picked up new abilities – firstly, we see it spit a wad of acid into a prisoner’s face, very much like some warrior ants who can even ‘self-destruct’ upon injury, drenching their enemies in toxins in the process. Furthermore, climbing, crawling Aliens in Aliens tended to need support, especially when crawling upside down, as the invading Aliens do during the Operations attack in Aliens. Fincher’s Alien, however, didn’t need any support at all:
Aliens hold on to piping for support...
…but not the “Runner”, who sticks to the ceilings like an insect. Director David Fincher told Cinefex, “We wanted the creature to walk on the ceilings and really sell the idea that this thing is a bug from outer space.”
Alien 3 also carries the dubious honour of being the first film in the series where a character outright calls the creature a bug, seen when Morse mocks the lead-drenched Alien, calling out, “I hate bugs!”
Ridley returned to bugs to help with Prometheus’ creature concepts. Writer Jon Spaihts told Empire magazine: “Ridley is a great and ghoulish collector of horrible natural oddities, real parasites and predators from the natural world. He had a tremendous file of photography of real, ghastly creatures from around the world – they’re chilling, some of them! He would tell these tales with relish, of waspsIt’s usually thought that would drill into the backs of beetles and plant larvae, or become mind-control creatures. Terrible things happen, especially the smaller you get. As you get into the insect world or the microbial worldelements began and ended with Cameron, savage atrocities are perpetrated by one creature on another. And Ridley was thrilledbut in fact not only did they begin with all of them. They inspired a lot of the designsDan O’Bannon, but they were continued and a lot of the ideas we triedpursued even by David Fincher for Alien 3.”