Research Area	Evolutionary developmental neurobiology
Lab Website	Lab Website
Google Scholar	Google Scholar
ResearchMap	https://researchmap.jp/TakayukiWatanabe/
E-mail	watanabe_takayuki (at) soken.ac.jp

Most insects undergo metamorphosis to develop into adults. The brains of holometabolous insects show drastic morphological changes during pupa, which are required to prepare for adult-specific behaviors. However, the brains of not all insects face drastic morphogenesis during postembryonic development. Approximately 10% of insect species belong to the evolutionary basal direct-developing insects, which develop into adults without pupation. Like holometabolous insects, adults of direct-developing insects exhibit adult-specific behaviors such as courtship and mating behaviors, which are not observed in juveniles. This raises a question from the viewpoint of evolutionary developmental biology: when and how the brain of basal direct-developing insects becomes adult brain without the pupal stage?
To address this question, we are investigating the neural circuits for adult-specific behaviors in a model direct-developing insect Gryllus bimaculatus (two-spotted cricket). In the current project, we focus on the sexually dimorphic circuits which may regulate sexually dimorphic behaviors such as courtship and ritual agonistic behaviors in adult male crickets and reveal the molecular basis and evolution of the neural sex-determination system in insects. Besides, we are establishing neurogenetic techniques (i.e., transgenesis and genome editing) in crickets for morphological, functional, and developmental analyses of neural circuits in the cricket brain.

Selected Publications, Books etc.

• 1.K. Tateishi, T. Watanabe (co-first author), H. Nishino, M. Mizunami, H. Watanabe. (2022) Silencing the odorant receptor co-receptor impairs olfactory reception in a sensillum-specific manner in the cockroach. iScience. 25:104272.
• 2.T. Watanabe. (2019) Evolution of the neural sex-determination system in insects: does fruitless homolog regulate neural sexual dimorphism in basal insects? Insect Molecular Biology. 28:807-827.
• 3.T. Watanabe, A. Ugajin, H. Aonuma. (2018) Immediate-early promoter-driven transgenic reporter system for neuroethological researches in a hemimetabolous insect. eNeuro. 5:e0061-18.2018.
• 4.T. Watanabe, H. Aonuma. (2013) Tissue-specific promoter usage and diverse splicing variants of the found in neurons; an ancestral Hu/ELAV-like RNA binding protein gene of insects, in a direct developing-insect Gryllus bimaculatus. Insect Molecular Biology. 23:26-41.
• 5.T. Watanabe, H. Takeuchi, T. Kubo. (2010) Structural diversity and evolution of the N-terminal isoform-specific region of ecdysone receptor-A and -B1 isoforms in insects. BMC Evol Biol. 10:40.