Pollination of Banksia ericifolia Smith: Birds, Mammals and Insects as Pollen Vectors

Abstract

In coastal heath, 12 km north of Sydney, Banksia ericifolia set fruit after cross-pollination but not after controlled self-pollination. Animals removed nectar and pollen from inflorescences during the day but not overnight. Introduced honeybees (Apis mellifera) and native birds (Meliphagidae, Zosteropidae) visited flowers frequently during the day, carried pollen on their body surfaces and were likely to transfer pollen between plants. Native bees, nocturnal moths and ants also visited flowers but were too infrequent, did not move between plants or foraged inappropriately to be important pollinators. No mammals were seen visiting flowers and the small mammals we caught carried no pollen. Exclusion experiments confirmed that pollination occurred during the day and not at night, but the experiments were insufficient to determine the relative importance of honeybees versus birds as pollinators. Only about 3% of the flowers of Banksia ericifolia developed follicles under natural conditions. Follicle production in this species was limited by resources and not by pollinators, since multiple cross- pollinations of flowers did not increase follicle production above the natural rate.

Do introduced honeybees affect seed set and seed quality in a plant adapted for bird pollination?

“…Plants that are considered to be adapted to vertebrate pollination are now increasingly visited by the invasive pollinator A. mellifera (Paton and Turner 1985;Vaughton 1992;Hansen et al 2002). Nevertheless the consequences of this phenomenon are poorly understood (Traveset and Richardson 2006).…”

“…England et al (2001) demonstrated that for Grevillea macleayana, pollination by honeybees in a vertebrate exclusion experiment produced a small but significant decrease in outcrossing rates. Vaughton (1996) found decreased seed set (50%) in inflorescences of the same species when birds were excluded compared to inflorescences where both birds and honeybees had access, while similar vertebrate exclusion experiments by Paton and Turner (1985) and Vaughton (1992) detected no clear effect on seed production in Banksia ericifolia or Banksia spinulosa respectively. However, none of these studies comment on seed or seedling quality.…”

“…In this study we tested the prediction that vertebrate exclusion and consequent pollination by honeybees would reduce seed set and seedling vigour for the vertebrate pollinator-adapted B. ericifolia (Carpenter 1978) which is also known to be frequently visited by honeybees (Paton and Turner 1985). We focused on three …”

“…This family features large, showy, nectar-rich inflorescences that are typically considered adapted to pollination by both birds and marsupials (Ayre and Whelan 1989) but are also highly attractive to both nectar and pollen-foraging honeybees (Paton and Turner 1985;Myerscough et al 2001). Honeybees have been reported to be effective pollinators of a range of Proteaceae (e.g.…”

Daily Torpor In A Pregnant Common Blossom-Bat (Syconycteris Australis: Megachiroptera)

“…Abundance of most insects (and other arthropods) and nectar strongly fluctuate (McFarland 1985;Paton and Turner 1985;Law 1994a). Occurrence of torpor during reproduction may thus be linked to the food consumed by the mammals.…”