Knowledge of how spatial and temporal environmental variation affects an ecological mutualism could reveal clues about mechanisms for the persistence and evolutionary origins of the mutualism. This study will focus on seasonal, site, and gender variation in the phenology of two dioecious fig species (Ficus, of which there are more than 500 altogether) and their pollinator wasps (including Ceratosolen marchali and Kradibia gestroi). The dioecious fig - fig wasp mutualism is of special interest because: 1) its persistence requires that wasps regularly enter and pollinate female fig flowers in which the wasps die, leaving no offspring, and 2) according to ideas relating seasonality to the evolution of dioecy, maintenance of the obligate pollinators requires that male trees flower at times when their success as pollen donors to female trees is small. How this mutualism persists seems therefore rather problematical. This study will investigate predictions formulated from studies of monoecious figs and a dioecious fig (Ficus carica), an ecological outlier exhibiting unusual phenology. Detailed observations of known (mapped) individual branches, together with hand pollinations, self-pollination, and choice experiments will facilitate tests of hypotheses regarding the persistence of this mutualism and various possible outcomes for each of the participating components. Studies will be conducted in protected deciduous and evergreen forests of Karnataka State, India. It may be that these figs, like many others, reign as keystone species in the forests in which they occur, heavily influencing the occurrence/absence of other particular plant or animal species within the same habitats.
