Insects in the theatre? (5)
I believe the answer is:
flies
'insects' is the definition.
(fly is a kind of insect)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for flies that I've seen before include "Insects; passes swiftly" , "Trouser zip area -- travels through the air" , "Insects; goes quickly" .)