Bugs in religious groups? (7)
I believe the answer is:
insects
'bugs' is the definition.
(I know this)
'in religious groups?' is the wordplay.
'religious groups?' becomes 'sects' (sect is a type of religious group).
'in'+'sects'='INSECTS'
(Other definitions for insects that I've seen before include "Ants, say" , "Bees, flies, etc." , "Unimportant people" , "Six-legged creatures" , "Considerable class" .)