Insects account for the majority of the described species. Most insects undergo morphological and behavioral changes through “metamorphosis” from larvae (nymphs) to adults. Their ability to adapt to various environments and food resources due to “metamorphosis” is one of the major factors contributing to the prosperity of insects. In addition, molecules involved in metamorphosis, which specifically function in insects, have been focused from the viewpoint of the pest control such as the development of insecticides harmless to vertebrates. Molecular mechanisms underlying insect metamorphosis have been studied primarily in holometabolous insects such as the fruit fly and the silkworm, which have a “pupal” stage between larva and adult. Meanwhile, insects without “pupal” stage such as locusts and cockroaches are known as hemimetabolous insects. Among hemimetabolous insects, damselflies and dragonflies undergo drastic morphological and behavioral changes from nymphs to adults without “pupal” stage, but the genes involved in metamorphosis had not been elucidated.

In collaboration with the University of Tokyo and Tokyo University of Agriculture, researchers in AIST analyzed the genes underlying metamorphosis in damselflies and dragonflies, and they identified three key transcription factors. The researchers discovered that one of the transcription factors, which determines the “pupal” traits in holometabolous insects, controls many genes important for nymphal and adult traits in damselflies and dragonflies without pupal stage. This finding significantly contributes to understanding of insect metamorphosis that underpin the insect diversity.