Division of Insect Sciences

Insect Growth Regulation Research Unit

Elucidation of the mechanisms of molting, metamorphosis, reproduction, and diapause in insects

 While insects cause a great deal of damage to crops as agricultural pests, silkworms and honeybees provide useful products for human life. Therefore, development of a new technology that enables artificial control of insect growth, development and reproduction is an important subject for agricultural productivity.
 The Insect Growth Regulation Research Unit performs the identification and functional characterization of genes involved in growth, development and reproduction in serious insect pests and beneficial insects such as brown planthopper and silkworm using genomic and biological information and develops practical applications of these genes. In particular, we focus on the identification and functional characterization of the genes involved in the actions of insect-specific hormones such as juvenile hormone (JH), ecdysteroids, and neuropeptides and the genes causing insecticide resistance. We also analyze the function of genes involved in development, regeneration, and diapause using RNA interference (RNAi) techniques. Based on the knowledge obtained in such studies, we aim for the development of novel insect pest control methods and the countermeasures for the insecticide-resistant pests.

Development of screening method for new JH agonists and antagonists using a candidate gene for JH receptor in Bombyx mori (BmMet2)

Structure of heteroptera-specific JH

JHSB3 (bottom) isolated from the brown-winged green bug, Plautia stali (top). This new JH is expected to serve as a target for the development of novel heteroptera-specific insecticides.

Knockdown effects engendered by RNA interference (RNAi) in adults and larvae of the sawfly, Athalia rosae

(a) Distal portions of thoracic legs are lost by interfering the Distal-less (Dll) gene that is essential to form wings, legs, antennae and mouthparts at pupal stage (right).
(b) Knockdown of the Dll gene during embryonic development caused deficiencies of distal portions of thoracic legs and mouthparts in newly hatched larvae (right). On the other hand, abnormality was not seen in the abdominal legs (prolegs) where the Dll gene function is dispensable.