Birth order as a source of diversification in spring phenology and its potential effects on performance in greater duckweed, Spirodela polyrhiza

The timing of both winter freeze-up and spring thaws are unpredictable and under these variable environments, clonal populations of Spirodela polyrhiza (greater duckweed) provide an excellent case study of phenotypic diversification as a risk aversion strategy. Previous research on this species has demonstrated that potential diversification bet hedging in the phenology of the production of turions is generated by birth order within clones. The timing of turion reactivation the following spring may also have profound fitness consequences due to the risk of the thaw and re-freezing of the water's surface. I therefore hypothesize that variance in turion reactivation phenology within clones is influenced by birth order of turions. This was tested through a laboratory study that determined the source of observed phenological variability, and an outdoor mesocosm study that further examined fitness consequences of variance in the timing of turion reactivation under different temperature treatments.