A great diversity offlower morphology in orchids has long been thought to be selected by diversepollinators.HabenariaWilld. (Orchidaceae) species are generally characterized by long nectar spurs and pollinatedby long-tongued insects (Lepidoptera), the mechanicalfit between the spur and pollinator proboscis length beingsupposedly caused by“arms race”reciprocal selection. Here, we report thatflowers ofHabenaria aitchisoniiRchb. f.with nectar spurs (approximately 9 mm) were pollinated by three species of settling noctuid moths whoseproboscises varied in length from 10 to 16 mm. When a settling moth crawled on the spikes and probed theflowersfor nectar, pollinia were placed on the moths’legs rather than on other body parts. Our 5-year survey of polliniamovement and 3-year supplemental pollination experiments indicated that fruit and seed production in this orchidwere not often pollen-limited atflower level. In a natural population in Shangri-La, Southwest China, the proportionsof pollinia removal and deposition on stigmas by moth legs were 93.8% and 83.5%, respectively. Thisfinding ofefficient pollen transfer by the pollinators’legs inH. aitchisoniiadds a new example of diverse pollinia placement onpollinators (here settling moths) in the Orchidaceae.
Effective pollinia transfer by settling moths’ legs in an orchid Habenaria aitchisonii
Year: 2019
