Bernhardt & Weston, The pollination ecology of Persoonia 
795 
third or fourth tepal on the same flower. Less frequently, it would fly to another 
flower or leave the site. In each case observ'ed the bee always depressed the tepal 
and probed for nectar before harvesting pollen from the tepal's anther. 
Variations on this mode of behaviour were observed at all sites in which female 
Leioproctus {Cladocerapis) species were common foragers. However, it was only at the 
Hilltop site that we observed that a Cladocerapis female would regularly depress all 
four of the tepals and rake pollen from each of the four anthers on the same flower. 
It contacted the stigma in two ways while foraging on the same flower. First, the 
bee's thorax and abdomen made dorsal contact with the stigma while foraging for 
nectar. Second, the thorax and abdomen made ventral contact with the stigma when 
the bee extricated herself from the floral tube and reversed herself to confront the 
anther. This movement provided the stigma with direct contact with the pollen 
laden, scopal hairs on the third pair of legs and with the 'apron' of hairs clothing the 
base of the underside of the abdomen. 
While bees in subgenus Cladocerapis and Exoneura species were the dominant pollinators 
of most Persoonia species they were too small to follow consistently from plant to plant 
within the study site. We did observe at the Big Badja Hill, Carrington Falls, Gungulla 
(Waterfall), Hilltop, Mt Tomah, Peats Ridge and Tianjara Falls sites that these two bee 
taxa would leave the flowers of one Persoonia shrub to visit those of its nearest 
neighbour. This occurred most often when the branches of different shrubs overlapped. 
Discussion 
Bees and wasps appear to be the major foragers on the flowers of Persoonia species 
native to eastern Australia. Taxa representing five out of the seven families of bees 
recorded in Australia (sensu Michener & Houston 1991) were collected on 19 of the 20 
species and one of the two hybrids in this study. However, only 23% of the insect taxa 
collected on Persoonia were both frequent visitors and consistent pollen vectors 
contacting dehiscent anthers and receptive stigmas while foraging for pollen and/or 
nectar. Field observations, insect collections and pollen load analyses indicate that 
only four or five out of the 26 taxa of Hymenoptera may be regarded currently as 
common or important pollinators of Persoonia species. This includes Exoneura species, 
perhaps three out of five Leioproctus (Cladocerapis) species and, possibly, the introduced 
honeybee (Apis mellifera). 
The role of the naturalised, A. mellifera, as a cross-pollinator of Persoonia is difficult 
to interpret. Workers forage actively for Persoonia pollen and the body of the insect 
contacts the Persoonia stigma during pollen harvest or nectar consumption. However, 
as A. mellifera collects pollen it moistens grains with nectar and transfers them to 
corbiculae on the hindlegs moulding them into damp pellets. The sugar in the nectar 
will cause the grains to hydrate early so they will lose viability in transfer. The 
dense, claylike consistency of a corbicular pellet does not lend the compacted grains 
to easy transfer to a stigma particularly when they are now so compressed and then 
propped up on the hind tibia away from the lower, stigmatic surface. In contrast, 
female bees in the Anthophoridae, Halictidae and genus, Leioproctus, all carry their 
pollen loose in granular masses between hair tufts ornamenting the hindlegs and 
underside of the abdomen (Bernhardt 1984, 1989, 1995, Michener 1974). These bees 
may transfer Persoonia more easily when they scrape or rub the basal portion of their 
hindlegs or abdomens against the stigma while searching for nectar or dehiscent 
anthers. The effectiveness of naturalised, A. mellifera, as a pollinator of Persoonia 
would appear to depend on the quantity of grains that adhere to the bee's head and 
thorax but miss the combing process and transfer to the corbiculae. 
