Having Nick at Gatsby's party provides an unprecedented chance to peer into the lives of the seemingly well-to-do people who attend. The impression is not very appealing. It turns out that the glamorous and glib party guests are, in fact, quite shallow. Nick says that they "conducted themselves according to the rules of behavior associated with amusement parks," again stressing the carefree, stereotypical roaring '20s atmosphere. Much to the partygoers' discredit, however, "sometimes they came and went without having met Gatsby at all." In stark contrast, Nick "as soon as [he] arrived . . . made an attempt to find [his] host."
The “moth” imagery is significant because it conveys a sort of unconsciousness that Gatsby’s party guests embody. Insects are traditionally viewed as unintelligent followers, traveling about without a specific purpose or reason. Likewise, the people attending Gatsby’s parties are overall superficial, bouncing around without purpose.
Furthermore, moths are particularly significant because they are tragic creatures; they move toward light for a sense of security, only to find that the light source is actually a harbinger of death. Comparing Gatsby’s guests to moths implies that they are attracted to the brightness of the party’s extravagance, yet unknowingly leading themselves towards self-destruction.
In this passage, Fitzgerald is explaining that as the night goes on, people are getting more and more intoxicated. Thus making everything seem different. (i.e the lights are brighter, and the pitches are higher)
There is the connotation of alcohol flowing thorough the party from