Honeyeaters and the Pollination Biology of Banksia prionotes (Proteaceae)

Abstract

Honeyeaters such as Phylidonyris novaehotlandiae and Lichmera indistincta forage preferentially in regions of Banksia prionotes inflorescences where nectar and pollen are most abundant, removing pollen from freshly opened florets and transferring some of it to the stigmatic grooves of other florets on the same or different inflorescences. Each floret is protandrous, with pollen dispersal occurring during the first 4-8 h following initial presentation and significant esterase secretion by the stigma commencing after this phase has ended. Foraging by honeyeaters results in considerable pollen movement between florets on individual trees, although B. prionotes appears to be highly self-incompatible. Movement of honeyeaters and pollen between inflorescences on different trees occurs less frequently than between those on the same trees. Nevertheless, outcrossing leads to penetration of styles by tubes formed by pollen grains deposited in stigmatic grooves in some instances. Despite the small size and isolation of the population studied, the resultant level of follicle formation per infructescence, and percentage seed set, are greater than for most other Banksia species for which data are available.