I should be doing alot of other things, but
isabeau was talking about a Star Wars/Stargate crossover, and it got me thinking.
In Eric Flint's
Mother of Demons, the aliens are K-strategy breeders: they spawn a hundred or a thousand little larvae or whatever, but let them fight it out until about the time they start to speak, and only then pick up the children and nurture them. Mollusks, at their basic physiology. (Humans are... whatever the other strategy is: few children, intensive early child-care)
In David Weber's Honor Harrington series, at the beginning, humans have developed various means of prolonging human life, and it's subsequently slowed down military advancement within the ranks to a crawl. War speeds it right back up again.
So. The Goa'uld. From the episode Hathor, we see a queen surrounded by a tub full of immature larvae, and really - how many of them are likely to become a System Lord? Not terribly many. Sure, they'll be implanted in a Jaffa, but those are their troops, their soldiers, their 'oh, let them die - I have more'. But even with a high attrition rate in the initial spawn, and subsequently in the ranks of the Jaffa, a fair number of infant goa'uld will reach maturity, and need implantation into a host.
For the established System Lords, this isn't a big deal. They are lords of all they survey, and nabbing a new host to replace the old one isn't exactly a problem. Finding the perfect one may be a little like going shopping - witness the Pilot episode (They wouldn't want to take hosts from their Jaffa - the familiarity of face would undermine the goa'uld's authority.) But what about all those newly adult goa'uld? Do they all get implanted? Perhaps a System Lord might choose one or two to serve as a second-in-command, but they're fairly jealous of their power. why would they want to essentially raise a competitor?
The larvae are useful when they are implanted in their Jaffa - they keep the army that supports the System Lords healthy and tightly bound to their masters. But as soon as they come out, they're competitors, fully cognizant of their subserviant role to the reigning System Lords, and incredibly, ruthlessly ambitious. (Something tells me I need to pay more attention to Peter Wingfield's appearance - I haven't watched that much SG-1 past the first season.)
If I were a System Lord, I'd make sure that the newly adult symbiotes had a fuck of a high attrition rate. Perhaps select two or three from a graduating class of however many Jaffa (it's going to be fairly steady, what with the coming-of-age ceremony used to creat new Jaffa), use them as lieutenants, and simply kill the rest. Which leaves some doubt as to the competency of the new goa'uld, and makes the whole selection process a little arbitrary.
Or maybe stick all the new goa'uld in shoddy reject hosts, and run them through a testing ground that kills off the 'unworthy' and reward the ones that come through alive with newer, better hosts. The Test will be designed to kill off as many as possibly, and that leaves the meanest, toughest larvae as the new lieutenants in the System Lord's forces. Sort of like boot camp on crack. It should reduce the number of newly adult goa'uld, give the larvae a hope of surviving much past adulthood (because they're such arrogant snots, they believe that of course they'll be the one to survive) and an entree into the military service of the goa'uld - a rank or two down from the System Lords, but if they're good and they carve their enemies into so many pieces, their System Lord will reward them with a planet or two to rule.
Look, Mom - Logic! I just hope I didn't trample over some canon I didn't know about.