Format: ORAL

Zong-Xin Ren1 Graham H. Pyke1,2

1. Kunming Institute of Botany 2. Macquarie University

Floral nectar is central to most relationships between plants and animal pollinators, and has been the subject of much investigation for a long time. However, much about nectar remains poorly known and understood. We know, for example, costs of floral nectar production to a plant are significant, however, relevant evidence is scant and difficult to interpret. Also unknown is the extent to which plant costs and gains associated with nectar production can be expressed in a single currency such as energy. There is also growing evidence that plants can both secrete and absorb nectar, possibly enabling them to regulate nectar attributes in their flowers and thus manipulate pollinator behaviour to their advantage. In some circumstances, floral nectar may also attract or repulse potential pollinators by virtue of its attributes, but such circumstances are likely rare. In this talk, we will present our new findings on cost, regulation and partner manipulation based on the evidence from multiple plant species pollinated by various animal pollinators in Australia and China. By doing a series of floral nectar removal, nectar reabsorption and artificial nectar addition experiments, we provide evidence of simultaneous nectar secretion/ absorption and consequent regulation for sugar volume, sugar concentrations and sugar type. We also show that some floral nectar attributes between neighbouring flowers within an individual plant are correlated in both bagged and open pollination treatments indicating potential partner manipulation.