A possibility of premating isolation mediated by female sex pheromones between the two subspecies of <i>Hierodula patellifera</i> distributed in Japan

Hierodula patellifera is the only widely distributed species in the genus Hierodula. The nominotypical subspecies ssp. patellifera is broadly distributed, while ssp. daitoana, an endemic subspecies, is found only on the Daito Islands, a group of oceanic islands 360 km from Okinawa, Japan. When H. patellifera males detect the sex pheromone released by females, they shake their bodies quickly (juddering movement). This behavior was observed in the males of both subspecies of H. patellifera. When the males of each subspecies were given volatiles from consubspecific or allosubspecific females that showed calling behavior, males of both subspecies showed the juddering movement only in response to volatiles from consubspecific females. This suggests that premating isolation mediated by sex pheromones has evolved between the two subspecies. However, as the two subspecies are allopatrically distributed, the differences in sex pheromone components do not appear to be the result of reproductive isolation driven by subspecies interaction.