Format: ORAL

Dario C. Paiva1, Adam B. Roddy1

1 Insitute of Environment, Department of Biological Sciences, Florida International University, USA

Climate change is altering the costs and benefits of plant investments in reproduction. Knowing the costs of flowers and the mechanistic linkages between floral traits and floral performance is crucial to predicting how plants will respond to these changes in the future. Yet, the physiological costs of flowers and the traits influencing these costs of floral production and maintenance remain poorly studied. A few studies have addressed how water and carbon costs relate to flower longevity, but these have been restricted to only a few genera and mostly to cultivated plants that were not growing under natural conditions. To address this fundamental knowledge gap, we investigated how flower longevity and size two traits associated with the likelihood of pollination are related to traits influencing the water and carbon costs of flowers in naturally occurring montane plant communities. We sampled 19 species belonging to 15 families in the endangered Brazilian campos rupestres, a montane ecosystem known for its high diversity and endemism. We found that variation in traits related to carbon construction costs (petal mass per area and petal thickness) was explained by the longevity of individual flowers, while traits related to water maintenance costs (residual conductance and water residence time) were associated with flower size. Our results showcase how the physiological costs of flowers are related to pollinator attraction and thus play an important role in plant reproduction. Furthermore, our results highlight that shifts in the relative strengths of pollinator and non-pollinator selection may alter floral traits depending on the physiological costs of the flower. Therefore, our results can provide insight into how flower production and function may be affected by different components of climate change.