A question of orphaned eggs.

[Leigh]

We haven't heard anything in the books about what might happen if something happened to a queen before her eggs hatched; the closest we got was poor Orlith being forced to stay with her eggs after Moreta died, and as soon as they were hard enough to hatch, she suicided.

But who would care for the eggs if a queen died before they were hard? Could another queen be talked into caring for them, or are they too territorial? Would humans have to somehow get the job done? Hell, could a gold wher be persuaded to brood over a dragon clutch?

[Heather]

There's also the case of Nemorth (DragonFlight), who stayed alive after her rider, Jora, died, long enough to stay by her eggs. Once they hatched she died. So a queen will live long enough to be with her eggs.

Queens don't fly Thread after they've clutched, and don't really leave the Sands much, which is why their bronze mates sometimes bring them food, so there's nothing that should plausibly happen to them that would cause their death and leave eggs orphaned.

[Leigh]

But what if something in the Cavern killed the queen?

[Paula]

If something in the Cavern is able to kill the queen, it will also kill the eggs, see poor Lenala. Dragons don't die that easily.

[Heather]

But what if something in the Cavern killed the queen?

Let's say the queen catches a rare dragoncase of the flu and dies The Sands are kept heated by themselves so they would still keep the eggs warm, and then the Sire of the eggs would probably hang around to watch and make sure no egg-thieving happened or that unauthorized humans weren't in the cavern (since Sires tend to hang out to see to the needs of the Queen who clutched the eggs.) I don't think Queens actually 'sit' and incubate eggs like birds, in the books it's always written as if they clutch the eggs and then make sure they're nicely situated in the Sand to remain heated throughout their incubation period.

So, I guess to answer your original question, I don't think another queen would come and be with the eggs, because I don't think another queen's presence would be required to have the eggs hatch.

[Avery]

I agree with the others that it seems highly improbable that a gold would die with eggs on the Sands. Anything in the Cavern that could kill her would likely also kill the eggs. Not much brings a clutching gold out of the Hatching Cavern. Anything that would be severe enough to need a queen dragon's response could likely be handled by other queens instead of her. If she was the only one available to responde and was killed, then would there be any other golds to babysit the eggs?

The only situation I can come up with would be the senior queen on the sands and then her two juniors nearly rise at the same time and have a fight. She steps in to break it up because only golds can stop this kind of fight. The fight is resolved but not before sustaining fatal injuries (or being dragged /between/ by one of the fighting golds.) Now the eggs are left behind and there's a (possibly-wounded) junior queen to watch them.

It might depend on the temperament of the gold left behind and on the strength of her rider's will. We know the golds are jealous when mating because they wan to keep the bronzes to themselves; they're territorial of their property. But they also can have two clutches on the Hatching Sands, albiet likely with a good amount of space between them. So if a gold didn't have her own clutch and had a strongwilled rider, the rider might be able to push her gold to help.

What kind of help is really needed for a clutch, though? Golds mostly seem to just guard their clutches from intrusion or maybe turn the eggs a couple times to ensure the sand hasn't got cold. They do it for their own eggs because they're invested in what they produced. Why not just ask the sire of the clutch  to do it? He might have the instincts. Or have other bronzeriders get their dragons to step in? One or two dragons on watch and occasionally checking temps seems like it should be enough.

[Eimi]

Hypothetically, there could be a disease that might affect only dragons.  Or there might be a deliberate attack through poison on the gold's life as an act of terror.  Though highly unlikely, I think it is definitely possible to have a queen die before her Clutch hatches.

In which case, I think the next Senior Queen would take charge of the Eggs.  It's her territory now, and those Eggs would be her "subjects" if you will.  It is in the best interest of the Weyr and in their fight of Thread for those Eggs to hatch successfully, so I think she would become their foster mother, guarding them and turning them (since that is something the Gold does I believe to make sure one side doesn't bake in the heat).  I don't think Gold's get territorial over Eggs, but they do over their Weyr.  Anything that benefits their Weyr becomes the Senior Gold's business.