A novel seed dispersal mode of Apostasia nipponica could provide some clues to the early evolution of the seed dispersal system in Orchidaceae

Despite being one of the most diverse families, scant attention has been paid to the seed dispersal system in Orchidaceae, owing to the widely accepted notion that wind dispersal is the dominant strategy. However, the indehiscent fruits, with seeds immersed in fleshy tissue, evoke the possibility of endozoochory in Apostasioideae, the earliest diverging lineage of orchids. In the present study, I investigated the seed dispersal system ofApostasia nipponicaby direct observation, time-lapse photography, and investigation of the viability of seeds passing through the digestive tract of orthopterans. This study revealed a previously undocumented seed dispersal system inA. nipponica, in which the cricket,Eulandrevus ivani, and the camel cricket,Diestrammena yakumontana, consume the fruit and defecate viable seeds. Orthopterans are rarely considered seed dispersers, but the gross fruit morphology and pigmentation patterns of someApostasiaspecies parallel those seen inA. nipponica, suggesting that similar seed dispersal systems could be widespread amongApostasiaspecies. Whether seed dispersal by orthopteran frugivores is common in Apostasioideae warrants further investigation.