After 26 generations of selection, a strain of house fly developed 430-fold resistance to fipronil.
Realized heritability (h2) value was 0.05 in fipronil selected house flies.
Fipronil selected house flies showed no cross-resistance to lambda-cyhalothrin, profenofos and indoxacarb.
There is a high risk of resistance development to fipronil.
Resistance management strategies are needed for suppression of house fly.