ZZ/ZW type ot sex determination is seen in

ZZ-ZW Type : This mechanism operates in certain insects (butterflies and moths) and in vertebrates (fishes,reptiles and birds). the male has two homomorphic sex chromosomes (ZZ) and is homogametic and the female has two heteromorphic sex chromosome (ZW) and is heterogametic. there are thus two types of egg: with Z and with W, and only one type of sperm i.e. each with Z.