PARENT SESSION
Friday, August 11, 8:00-11:30 am
COS 106 - Species interactions: mutualism, symbiosis, and parasitism
L-3, Lobby Level, Cook Convention Center
Presiders: L Altfeld
Between a rock and a hard place: parasites, population size, and fruiting asynchrony in the Sonoran Desert rock fig, Ficus petiolaris.
Stireman, John*,1, Nason, John *,2, 1 Department of Biological Sciences, Dayton, OH, USA2 Department of Ecology, Evolution, and Organismal Biology, Ames, IA, USA
ABSTRACT- Mutualisms are ubiquitous and profoundly influential in shaping the evolution and ecological interactions of plants and animals. Our understanding of mutualisms, however, has suffered from a lack of geographical and ecological context. To provide insight into how the stability of mutualisms may be shaped by environmental variation and parasites, we assessed the impact of parasites on the fitness of a fig-fig wasp mutualism and examined how this impact varies with population size associated with a precipitation gradient. Our preliminary results along with published simulation studies of the influence of population size on pollinator extinction risk suggest that: 1. Some, but not all, fig parasites are negatively associated with pollinator production, 2. At least some fig parasites are negatively associated with seed production, while pollinator production is positively correlated with seed production, 3. Parasite abundance appears to be positively associated with small populations and harsh environmental conditions (low precipitation), 5. small fig populations are at high risk of pollination extinction. We hypothesize that changes in reproductive timing in the figs may mitigate dangers of pollinator extinction and mutualism breakdown in harsh environments, and conversely, that they may destabilize the mutualism because parasites of the mutualism may be able to take advantage of altered reproductive schedules better than pollinators. We propose that these conflicting selection pressures may serve to limit the distribution and dynamics of Ficus petiolaris.
Key words: mutualism stability, parasite, Ficus