Ok, similar questions here & possible answers about these odd items. I posted the link. Informative anyway, especially about your other question about Dead But Satisfied.
I've checked the posted links but still find no reference to my odd Roisterer or your Swallowtail. However, the Moth/Butterfly seems a pretty obvious link. As to what, I have no idea.
If it was an old quest, surely someone would remember and there'd be a Collection slot or Quest string listed?
As far as I know, there is no GI allowed interaction between IPad players, FB or Andriod either. With the exception of the odd Discussion thread, we are all iPad players here.