1
general::
Become wildly excited or enthusiastic. For example, The audience went ape over the band. This idiom is a modern version of the older GO BERSERK. It fancifully equates frenzy with an ape's behavior. [Second half of 1900s] Also see GO BANANAS.
American Heritage Idioms
2
general::
Phrase(s): go ape (over someone or something)
Sl. to become very excited over something. • I just go ape over chocolate. • Sam went ape over Mary.
McGrawhill's American Idioms And Phrasal Verbs