>>107670409The dead host can be used as food for the newborn, though this is downplayed since in the movies, the aliens go from snake sized to fully grown in 15 minutes without taking in any sustenance.
Additionally, the original idea for their life cycle was that they wound people, cocoon them, and the cocoon turns into the egg. This was changed into an insectoid matriarchy in the second movie, where a queen lay eggs. The parasitic larvae is also a treat found in certain wasps species, which implant their larvae into living hosts.
Beyond that, killing the host in a violent outburst allows more efficient escape for the newborns, which is potentially a life saving mechanism in a hostile environment. The newborn can quickly emerge and slither away; possibly at a great distance from the initial point of impregnation, allowing the species to travel to great distances with their hosts (they also absorb DNA from the victims, changing their characteristics, which is why Big Chap had a human skull and the predalien had predator mandibles). Re-using the victim only works if the victim is held down, like in the middle of the hive, and it also assumes that the aliens have to go to lengths at keeping them alive for any period of time - feeding the hosts, etc. It's not that efficient.
And speaking of Predalien, that dude could orally impregnate 5-6 alien larvae simultaneously into the bodies of already pregnant women. That scene in the movie gave me a boner, is that weird?
