The moths are Luna Girl's minions (and the only friends she has).
On some occasions, the moths can unite to carry Luna Girl around by flight when she doesn't use her Luna Board. In certain situations, they attempt to warn Luna Girl of impending misfortune, even though she tends to ignore them. They also have the ability to make noise to mimic human language and sometimes try to communicate with Luna Girl.
They follow all of Luna Girl's orders and attempt to complete them to the best of their ability. The moths love her, despite her often mean and verbally-abusive treatment to them.
The moths are small and white in appearance. They are each about the size of Luna Girl's fingers but can be large when flying in groups.
Even though Luna Girl can treat them quite poorly in some episodes, they still appear to care for her.
They almost left her in "Catboy and the Butterfly Brigade" after a large amount of criticism and mistreatment, but went back to Luna Girl when she became sad about it.
They may be able to partly speak in English, as they sang the "We can't think of a rhyme!" portion of the PJ Masks' theme song in "Catboy's Tricky Ticket".