Ralph longs from some connection to the adult world to show that they aren’t alone, but the adult is dead, so they are alone.
Ralph comments that adults are not afraid, and they don’t argue. They sit down and talk things out. He wishes for a sign from the adults about how to proceed. He feels very frustrated and overwhelmed by the responsibility of being chief.
“If only they could get a message to us,” cried Ralph desperately. “If only they could send us something grown-up.. . . a sign or something.” (ch 5)
When Sam and Eric see the “beast,” it is really just a parachutist. They do not know this though, and their imaginations run away with them. Narratively, the parachutist is a metaphor. It signifies that there will be no sign, and the boys are on their own.
Not only do they get no signal from the outside world, but their ability to communicate with the outside world via the fire is also compromised, since they have trouble keeping the fire going and the fire is considered their best chance to communicate with the outside world (and the adults) and be rescued.