Effects of drought on floral traits that influence pollination

Background/Question/Methods

Pollinators play an essential role in the maintenance of wild plant diversity and the agricultural production of food. We studied how climatic changes may influence plant-pollinator interactions, focusing on how drought affects plant traits that mediate the interaction with pollinators. Furthermore, we asked how local adaptation to soil moisture may influence the way floral traits respond to drought, using a serpentine-tolerant plant species. Serpentine-tolerant plants are useful in studying how local adaptation may mediate responses to water limitation because serpentine soil is highly drought-prone. We collected seeds from populations of the serpentine-tolerator Antirrhinum vexillocalyculatum from serpentine and non-serpentine sites. We then sowed seeds in a greenhouse and exposed plants to drought or control water levels. We quantified floral size and the amount and quality of food reward to pollinators.

Results/Conclusions

We found some evidence that local adaptation mediates the way drought affects floral traits. Drought reduced floral size and also reduced the amount of nectar and the amount of sugar in nectar. These results imply that with future climatic changes both the attractiveness of flowers and the food provided to pollinators may be compromised.