Cymbidium kanran can deceptively attract Apis cerana for free pollination by releasing specialized volatile compounds

Abstract: Pollination is a crucial aspect of plant reproduction and evolution. To explore the pollination biology of Cymbidium kanran, detailed studies were conducted on its flowering phenology, breeding system, volatile components of flowers, and the behavior of pollinating insects. The results showed that: 1) C. kanran does not have self-pollination or apomixis and requires a pollination medium to produce seeds. However, the natural fruit set rate is much lower than that of artificial pollination, indicating a serious pollination limitation. 2) The effective pollinating insect for C. kanran is Apis cerana, which carries both the pollinia and anther cap during pollination. C. kanran does not provide any reward such as nectar or edible pollen to the pollinators. 3) The glass cylinder experiment showed that the flower color of C. kanran is not attractive to pollinators (p=0.1341>0.05), while the scent is significantly attractive (p=0.00040.017<0.05), although the color of C. kanran is one of the most diverse species within the Cymbidium genus. 4) Based on the dynamic changes of volatile components of flowers during different flowering periods, it is speculated that hexanal, heptanal, octanal, 2-pentyl furan, 4-methyl-2-pentanone, and 1,4-cyclooctadiene may be the volatile components that attract pollinators. 5) The population size, number of flowering individuals, number of flowers, and the movement of pollinia have a highly significant positive correlation, but the population size is not correlated with individual reproductive success (p=0.112~0.185>0.05). This study provides scientific basis for the wild resources conservation and breeding in C. kanran.