insect vs ladybug

insect

noun
  • Any small arthropod similar to an insect, including spiders, centipedes, millipedes, etc. 

  • An arthropod (in the Insecta class) characterized by six legs, up to four wings, and a chitinous exoskeleton. 

  • A contemptible or powerless person. 

ladybug

noun
  • Synonym of ladybird. 

How often have the words insect and ladybug occurred in a corpus of books? (source: Google Ngram Viewer )