The Diascia flower and its bee – an oil-based symbiosis in southern Africa

As has been formerly shown, the double-spurred flowers of the South African genus Diascia (Scrophulariaceae) produce fatty oil as a primary attractant. Their oil-collecting pollinators have so far remained unknown. It is concluded from the morphology and from direct evidence of flower visitation that the recently established Melittid genus Rediviva represents the co-evolved pollinator group of these plants, at the same time demonstrating the presence of “manual” oil collectors in Southern Africa. The bees must introduce their especially equipped forelegs into the paired spurs of Diascia for harvesting the oil, thereby pollinating the flower. In the described case, a new species, Rediviva emdeorum, has extremely elongate front legs which perfectly fit the spurs of Diascia longicornis.