Embryonic thermosensitive TRPA1 determines transgenerational diapause phenotype of the silkworm, <i>Bombyx mori</i>

Significance Diapause has evolved as a specific subtype of dormancy in most insect species and as a seasonal polyphenism that ensures survival under unfavorable environmental conditions and synchronizes populations. In Bombyx mori , embryonic diapause is induced transgenerationally as a maternal effect. However, the molecular mechanisms involved in the perception of environmental temperature and in linking thermal information to neuroendocrine functions are still unknown. Here, we show that the Bombyx transient receptor potential A1 (TRPA1) could be thermally activated during embryogenesis, and an unknown signaling pathway linked to the release of diapause hormone may then be activated to affect the induction of diapause in progeny. The Bombyx TRPA1 acts as a molecular switch for the development of an alternative phenotype in an animal with seasonal polyphenism.