The Phenology of Dioecious Figs in Singapore
Speaker: Nanthinee Jeevanandam (Graduate Student, Department of Biological Sciences, NUS)
Date: 18th May 2009 (Monday)
Time: 9:00 AM
Venue: Seminar Room 2 (SR2) S2, 04-10
Supervisor: Prof Richard Corlett
Dioecious figs have a complex, obligate mutualism with their pollinators, the fig wasps (Insecta: Agaonidae). To add to this complexity, parasitic fig wasps compete with pollinating wasps for oviposition sites in receptive, functionally male figs. This often has a negative impact on the number of potential pollinators produced in the next generation, which are needed to pollinate fig populations. To further complicate matters, parasitic fig wasps come in different forms; gallers, parasitoids and parasites, all having a different impact on the pollinating fig wasp population sizes.
In a relationship between long-lived woody plants and short-lived wasps (adult life span 2-3 days), precise timing is crucial, since even a brief gap could result in the local extinction of pollinators and/or parasites. In monoecious figs, this has resulted in the evolution of a plant phenology whereby fig crops are synchronized within a plant but not between plants. In dioecious figs, in contrast, the phenologies of different fig species are much more varied suggesting that that there may be multiple alternative solutions to the timing problem, with the evolutionary choice depending on other factors, including climatic seasonality, growth form and ecological role. Volatile organic compounds synchronize timing between the plant and pollinator, but their role in attracting non-pollinators is currently unknown. Understanding what makes this delicate balance successful will provides us with insight into the persistence of dioecy in figs.