抄録
Floral scents are among the key adaptive traits which facilitate plants' reproductive success through guiding specific pollinators to flowers, and their role as the olfactory cue for pollinators has likely been maintained and evolved since the origin of insect pollination in the Mesozoic gymnosperms. Because the component compounds of floral scents are highly diverse, they function as complex and specific signals for pollinators, thus the evolutionary changes of the individual components of floral scents can lead to plant speciation through switching of pollinators. This means that the floral scent traits, targeted by natural selection, can act as the driver of plant diversification. To examine this hypothesis, I highlight the genus Asimitellaria (Saxifragaceae) which consists of 14 species endemic to Japan and Taiwan, indicating that its diversification has been centered in the Japanese Archipelago. In Asimitellaria, the principal pollinators are a limited species of fungus gnats (Mycetophilidae), and our research group demonstrated that the multiple pollinator switches between long-tongued fungus gnats and short-tongued fungus gnats have taken place in association with the loss or gain of the floral volatile containing lilac aldehydes. Ongoing research has identified the candidate genes responsible for the floral scent changes, and the examination of whether these genes are the “speciation genes” are underway.
