Anglers welcome them, but not from insects (5)
I believe the answer is:
bites
'insects' is the definition.
Although both the answer and definition are plural nouns, I cannot see how they can define each other.
'anglers welcome them but not from' is the wordplay.
'anglers welcome' becomes 'bit' (I can't justify this - if you can you should believe this answer much more).
'them' becomes 'foes' (I've seen this in another clue).
'but not' is a deletion indicator.
'from' becomes 'of' (of can mean from or belonging to).
'foes' with 'of' removed is 'es'.
'bit'+'es'='BITES'
Can you help me to learn more?
(Other definitions for bites that I've seen before include "Tears with the teeth" , "Mouthfuls" , "Morsels" , "Breaks with the teeth" , "Stings" .)