Arrhenotoky (from Greek -τόκος -tókos "birth of -" + ἄρρην árrhēn "male person"), also known as arrhenotokous parthenogenesis, is a form of parthenogenesis in which unfertilized eggs develop into males. In most cases, parthenogenesis produces exclusively female offspring, hence the distinction. Arrhenotoky occurs in members of the insect order Hymenoptera (bees, ants, and wasps) and the Thysanoptera (thrips). The system also occurs sporadically in some spider mites, Hemiptera, Coleoptera (bark beetles), and rotifers.