Effectiveness of Invertebrate and Vertebrate Pollinators and the Influence of Pollen Limitation and Inflorescence Position on Follicle Production of Banksia aemula (Family Proteaceae)

Abstract

Follicle development of Banksia aemula (R.Brown 1810) was studied in northern New South Wales, Australia, after exposure of inflorescences to different combinations of pollinator type and pollen quantity. When inflorescences within plants were exposed to all pollinators and provided with additional cross-pollen, follicle development was increased, suggesting that B. aemula was pollen-limited. The addition of cross-pollen did not increase follicle development when inflorescences within plants were exposed to invertebrate pollination only. Nor did exclusion of vertebrates significantly reduce follicle development of plants relative to that of others which were exposed to all pollinators. The vegetation surrounding plants influenced the follicle development of inflorescences, and inflorescences in peripheral positions had more follicles than inflorescences that were internal.