The role of non-flying animals in the pollination of Banksia nutans

Abstract

Banksia nutans is a common, 1 m high, bushy shrub that flowers over summer in the sandplain heathlands on the southern coast of Western Australia. It appears to be principally pollinated by the honey possum, Tarsipes rostratus. This tiny (7–10 g) marsupial is the most abundant and widespread mammal in one large heathland where 97% of honey possums trapped near B. nutans were found to carry its pollen. An experiment was conducted that regulated access to flowers by different groups of pollinators. Exclosures around bushes removed access to flowers by flying animals, but still allowed honey possums to visit the flowers. This treatment resulted in fruit set that was not significantly different from bushes to which all animals had access. Exclusion of animal visitors resulted in significantly lower (albeit substantial) fruit set. This indicates a capacity for self-pollination that may offset the apparent reliance of Banksia nutans on honey possums for pollination.