Animal and insect run away together (8)
I believe the answer is:
antelope
'animal' is the definition.
(I've seen this before)
'insect run away together' is the wordplay.
'insect' becomes 'ant' (ant is a kind of insect).
'run away together' becomes 'elope' (I've seen this in another clue).
'ant'+'elope'='ANTELOPE'
'and' acts as a link.
(Other definitions for antelope that I've seen before include "it runs very quickly" , "Springbok, perhaps" , "Animal related to goat" , "grazing animal" , "Springbok or gnu?" .)