Does Ralph understand Piggy's fears at the beginning of Lord of the Flies?

Toward the beginning of the story, Ralph sympathizes with Piggy's fears but does not fully acknowledge them until Jack officially establishes his own tribe of savages at the opposite end of the island. Ralph and Piggy have similar goals and wish to establish a civil society, where each boy follows directives and completes necessary tasks that will increase their chances of being rescued. Despite Ralph's affinity for civilization, he does not fully grasp Jack's malevolence and his potential for savagery, which are character traits that Piggy immediately recognizes. Ralph is an athletic, attractive boy, who has been elected leader of the group, which is in stark contrast to Piggy's physical description and social standing. Piggy is an unathletic, overweight adolescent, who is the weakest older boy on the island and solely relies on others' civility to survive. Due to their extreme differences and social roles, Ralph does not fully comprehend Piggy's fear at the beginning of the novel. Ralph initially views Jack as an irritant, who is jealous that he was not elected leader. In contrast, Piggy immediately recognizes Jack's nefarious personality and is aware that he is a violent boy, and that he would harm weaker members of the group if given the opportunity. It is only after Jack physically threatens Ralph and establishes his own tribe of savages that Ralph fully understands Piggy's fear.

The respective fears of Ralph and Piggy are very closely aligned. Piggy is frightened that he will not survive life on the island. As an overweight, shortsighted boy, he knows he is a prime target for bullying from Jack and his tribe. In a dog-eat-dog society in which only the fittest can survive, Piggy starts off with a lot of natural disadvantages. Because of that, he has to rely on Ralph as his protector in this harsh, unforgiving environment.
Ralph, for his part, understands that it is essential for the boys' survival that they form a rules-based society in which everyone pulls together for the good of the whole. Such an arrangement is the only way to protect the vulnerable members of society such as Piggy and the littluns. Otherwise, there will be anarchy, and the stronger boys will simply dominate and terrorize the weaker ones. Tragically, Ralph's and Piggy's fears are more than amply justified by subsequent events.