lovebug vs sugar-plum

lovebug

noun
  • A person who is in love; a sweetheart. 

  • An insect, the honeymoon fly (Plecia nearctica, family Biblionidae). 

sugar-plum

noun
  • Term of endearment: sweetheart, darling. 

  • A round or oval sweet/piece of candy made of boiled sugar. 

How often have the words lovebug and sugar-plum occurred in a corpus of books? (source: Google Ngram Viewer )