Without hesitation parent produces insect (4)
I believe the answer is:
moth
'insect' is the definition.
(I know that Pterygota parent taxon insect)
'without hesitation parent' is the wordplay.
'without' is a deletion indicator.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'parent' becomes 'mother' (type of parent).
'mother' with 'er' removed is 'MOTH'.
'produces' is the link.
(Other definitions for moth that I've seen before include "Fairy like 13" , "Night-flying insect" , "Night-flier" , "Shakespearean fairy?" , "Cloth-eating larva" .)