Swift perhaps to pursue boy with unknown bug (8)
I believe the answer is:
ladybird
'bug' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Maybe there's a link between them I don't understand?
'swift perhaps to pursue boy with unknown' is the wordplay.
'swift perhaps' becomes 'bird' (swift is a kind of bird).
'to pursue' means one lot of letters go next to another.
'boy' becomes 'lad' (informal term for boy).
'with' says to put letters next to each other.
'unknown' becomes 'y' (algebra).
'lad'+'y'='lady'
'bird' after 'lady' is 'LADYBIRD'.
Can you help me to learn more?
(Other definitions for ladybird that I've seen before include "that's spotted in gardens" , "Kind of beetle" , "Spotted creature" , "old children's book" , "This insect likes greenfly" .)