Flies generally pollinate ceropegias. The special tubular structure of the flowers is specifically adapted to capture the pollinators. On the inside of the tube (especially at the mouth and above the basal inflation), hairs are found, all of them directed downwards. When a pollinator enters the cage and moves down the tube, the stiff hairs make it difficult, if not impossible, to move out again. The insect is thus almost forced to move further down where a very specialized structure containing the pollen mass is housed. In the flower, pollen sacks get attached to the bodies of the pollinators. After 2–4 days, the flowers start to wilt. When this happens, the hairs become lax and the pollinator can leave its temporary prison. Pollination taking place when it enters another flower and depositing the pollen sacks in special rails where the pollen germinate, growing to the ovaries where fertilization take place. These flowers are described as myiophilous (fly-pollinated) pitfall-traps.

Heiduk et al. (2016) described a new pollination strategy in Ceropegia. They discovered that the trap flowers of Ceropegia sandersonii mimic compounds secreted by honeybees in distress. These volatile compounds are supposed to attract other honeybees to help the one(s) in distress, but food-stealing flies (the pollinators of Ceropegia sandersonii and flies of the Milichiidae family) are also lured to the supposed food source. The carnivorous flies are, however, deceived in that they follow the scent to a flower of C. sandersonii instead of the food (honeybee). The flowers are thus a chemical mimic of a food source of adult carnivorous flies. In search of food, the temporarily trapped fly will crawl around inside the flowers and the pollen, which are aggregated into tiny pollen masses, will eventually stick to some part of the fly (usually the proboscis or one of the legs), by means of a specialized ‘clip’. The flowers only last 2–4 days and when it wilts, the hungry fly will crawl out as the hairs in the tube loses its turgor and the fly can escape. Hopefully another flower will be in the vicinity to trick such a hungry fly to visit it in turn and deposit the pollen mass, to ensure successful pollination – usually to the detriment of the fly, as many dead flies are usually observed within the base of the tubes of flowers when dissected. According to Heiduk et al. (2016) Ceropegia sandersonii is one of the first plants to be identified that uses a so-called ‘betrayed thief’ strategy for pollination.

The few follicles that form are evidence of the specialized pollination strategy. Each follicle, however, produces a large amount of seed. The seeds are mainly wind-distributed and are dispersed by floating on the gentlest breeze with their parachute-like tufts of white hairs.

This species, like most ceropegias, are widespread but with low population densities. When not flowering, the plant is very difficult to detect among the surrounding vegetation.

Possible pollinators of Ceropegia are attracted from a distance by the odour or the nectar, sometimes sweet but usually putrid smelling. Once in the vicinity of the flower, there are further attractants such as colours and hairs, which may be fixed or vibratile in a slight breeze. When a visiting insect, such as a small fly, crawls around in the flower it may get its proboscis or a leg caught in the guide to the pollen masses which may then be extracted from the staminal column, by a greater or lesser degree of force. Subsequently the insect may then deposit one or both pollen masses on one of the 5 stigmatic surfaces fused with the top of the staminal column and by this means cause effective pollination (Dyer 1983) – during dissections of the inflated base many Ceropegia flowers one would usually find trapped insects or flies in the swollen base of the corolla. Stingless bees have also been reported to visit the flowers of Ceropegia sandersonii.

Figure 10. Diverse expression of the corolla in some South African Ceropegia species. A, Ceropegia distincta subsp. haygharthii; B, C. nilotica; C, C. radicans subsp. smithii; D, C. racemosa; E, C. ampliata; and F, C. cimiciodora. (Photos A–C by Geoff Nichols; D & E by S.P. Bester; F by Martin Heigan)