Insect with a lot to learn? (8)
I believe the answer is:
greenfly
'insect' is the definition.
(greenfly is a kind of insect)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for greenfly that I've seen before include "Garden pest" , "Common aphid" , "Pests" , "Common aphids" .)