CurvisetoneAMale-Specific Tricyclic <i>nor</i>-Diterpenoid from theSpringtail <i>Sinella curviseta</i>

The structure determination and occurrence of curvisetone (<b>1</b>), a tricyclic nor-diterpenoid from the tiny Collembola <i>Sinella curviseta</i>, is reported. Utilizing NMR analysis and mass spectrometry, we identified curvisetone’s unique carbon skeleton and its occurrence in various sex and life stages. Curvisetone, carrying an unprecedented carbon tricyclic ring system, is an example of the distinct terpene usage of Collembola, which differentiates them from other arthropods.