Buzzing insects' queen producing extract (12)
I believe the answer is:
quintessence
'extract' is the definition.
(thesaurus)
'buzzing insects' queen' is the wordplay.
'buzzing' indicates anagramming the letters (letters buzz around).
'insects'+'queen'='insectsqueen'
'insectsqueen' anagrammed gives 'QUINTESSENCE'.
'producing' is the link.
(Other definitions for quintessence that I've seen before include "The most perfect or typical example" , "Personification" , "Central aspect (of something)" , "Essential feature; embodiment" , "Purest manifestation" .)