Variety of aster eaten by animals (5)

I believe the answer is:
tares
Here is my best explanation:
'eaten by animals' is the definition.
Although both the answer and definition are plural nouns, I can't understand how they can define each other.
'variety of aster' is the wordplay.
'variety of' indicates anagramming the letters.
'aster' anagrammed gives 'TARES'.
Can you help me to learn more?