Songs of workers crossing border (7)
I believe the answer is:
anthems
'songs' is the definition.
(anthem is a kind of song)
'workers crossing border' is the wordplay.
'workers' becomes 'ants' (worker ants).
'crossing' is an insertion indicator (to cross can mean to go over or around).
'border' becomes 'hem' (I've seen this before).
'ants' placed around 'hem' is 'ANTHEMS'.
'of' is the link.
(Other definitions for anthems that I've seen before include "songs of praise" , "National songs" , "Songs of loyalty" , "Church songs" .)