Hawkmoth pollination of Bonatea speciosa (Orchidaceae) in a South African coastal forest



Hawkmoths (Theretra capensis and Hyles lineata livornica) pollinated the orchid Bonatea speciosa at a forested site along the southern Cape coast of South Africa. The flowers of B. speciosa are strongly evening-scented and hawkmoth activity was confined to a short period of 40 minutes after dusk on each evening of observation. The pollinaria are exceptionally elongated (c. 20 mm in length) and are affixed to the eyes of the hawkmoths. Pollinaria attached to feeding hawkmoths are brushed over the long stigmatic arms which project in front of flowers. The flowers of B. speciosa have a toothlike process at the mouth of the spur which forces moths to enter the flower from either side. As a result, only one of the pollinaria is removed from the flower during a visit. The division of the flower into two functional units by the toothlike process in the spur distinguishes the floral mechanism of B. speciosa from other Habenariinae.