Height conserved by two insects and huge beast (8)
I believe the answer is:
behemoth
'beast' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for behemoth that I've seen before include "Monster" , "Huge or monstrous person or thing" , "big beastly type" , "Something huge and monstrous" , "Something abnormally large and powerful" .)