Protea nectar and satellite fauna in relation to the food requirements and pollinating role of the Cape sugarbird.

Abstract

The nectar of Protea repens, a preferred food plant of the Cape sugarbird, Promerops cafer, contains on average 11.7 g/100ml of reducing sugars. but very low concentrations of protein and amino acids. Satellite insects are also taken by the sugarbird and the highest mean biomass of insects recorded in a single inflorescence was 86.0 mg (dry mass). These data, together with an estimate of the daily energy budget of the sugarbird, show that the birds must visit a very large number of blooms daily to satisfy their energy requirements. In doing so they fulfil an important requirement of an ideal pollinator.