With only several basic themes in all of literature, these themes certainly recur in all genres. Nonetheless, the treatment of these themes often greatly differs. Themes that are dominant in both the novel Lord of the Flies and the play Romeo and Juliet are Appearances vs. Reality, Light vs. Dark, and Prejudice/Hate although they are treated differently.
Both narratives begin with the theme of prejudice. The first scene of Romeo and Juliet touches upon the long-standing hatred of the Capulets and Montagues. As soon as the "star-struck lover," Juliet, learns that Romeo is a Montague, she acknowleges this bias, "My only love sprung from my only hate! (1.5.). This hatred of the feuding families prevails throughout the drama, culminating in the acrimonious exchange between the fiery Tybalt and the changeable Mercutio. Even in the final scene prejudice is exemplified in Paris's remark
This is that banish'd haughty Montague
That murdered my love's cousin—with which grief
It is supposed the fair creature died—
And here is come to do some villanous shame
To the dead bodies. I will apprehend him. (5.3.49-53)
and Romeo's hasty murder of him.
In the exposition of Lord of the Flies, prejudice is evident in Ralph's initial reaction to the nearsighted, overweight boy who asks him not to call him 'Piggy':
Ralph danced out into the hot air of the beach and then returned as a fighter-plane, with wings swept back, and machine-gunned Piggy.
Of course, Jack's antipathy for Ralph rises to the combative level as their relationship is much like the rivalry of Tybalt and Romeo as Ralph seeks to ameliorate relationships as does Romeo while both Tybalt and Jack are fiery and bellicose, simply wishing to overpower their rivals.
Appearances vs. Reality
Throughout Romeo and Juliet, characters form erroneous judgments based upon appearances. For instance, Tybalt assumes in Act III that Romeo is still his enemy, not knowing that Romeo has married his cousin, the parents of Juliet assume that their daughter is yet unmarried, Romeo assumes that Paris comes to do harm to Juliet's body at the tomb, and Balthasar and Romeo both assume that Juliet is really dead.
Similarly, in Lord of the Flies, there is often conflict between Piggy's rationality and Ralph's dreamy illusions--"Ralph settled himself for his nightly game of supposing" (10). The other boys, too, engage in illusion as they attribute their fears and innate savagery to "the beast." And, at times, there is even a blurring of appearance and reality as Piggy excuses their complicity in the death of Simon as he rationalizes that he and Ralph were on the outside of the circle and did not participate in anything. Even the others delude themselves: "In the silence that followed, each savage flinched away from his individual memory" (10). Of course, the motif of masking in both works falls under this theme as Romeo masks himself at the Capulet party and Jack masks his brutal savagery, making it easier to kill by painting his face.
Light vs. Dark
In both works, the symbolism of thematic light and dark figure prominently. But, whereas for Romeo and Juliet there is safety in the dark of night, for the boys of Golding's novel, the night presents dangers and evil as the boys' fantasies and fears crescendo in the night. For both Romeo and Juliet and the boys on the island the sun is dangerous. But, for the lovers it is reveals them while it blinds the boys.