Diversity of flower colors in plant-pollinator communities

Flower colors play an important role as a signal in plant-pollinator interaction. Flower colour may partly be shaped by a coevolutionary process in a geographic mosaic that is influenced by the structure of the flowering plant-community and their interactions with the local pollinator community.

If a plant community is structured by competition for pollinators, it should be advantageous for a plant species to evolve a flower color distinct from co-flowering plant species to attract pollinators. However, the sympatrically flowering species that share pollinators may benefit from each other raising local pollinator abundance and a facilitation effect may override competition. In a community assembled through facilitation, trait convergence would be expected and flower colors should be more similar than under influence of competition. This raises the question if flower colors can help to explain the assembly of plant communities, through evolutionary patterns and plant-pollinator interactions?

Plant-pollinator-networks represent inventories of the interactions in a plant-pollinator-community at a certain time and can thus be used to study the hypotheses raised above. Do plants that share the same pollinators differ from or resemble each other? Especially, are specialist plant species more likely to look like generalist plant species or to be different from them to achieve pollination?

Invasive plant species are a special case. They usually share no evolutionary history with the native plant species and can thus give useful hints to the process of community assembly. Can they invade an existing plant community because their flower phenology allows them to exploit local pollinator resources? To test this I will look at the flower colors of invasive plant species and their position in plant-pollinator-networks. Additionally, I conduct field experiments with invasive plant species to determine whether the invasion process is influenced by competitive exclusion or facilitation in respect to native plant species.

My work is in cooperation with the group of Prof. Rodrigo Medel (www.coevolucion.cl) at the Universidad de Chile, Santiago. I measured flower colors of Chilean plant species at different localities using a portable Photospectrometer, and I conducted field experiments in a nature reserve north of Santiago. To analyse data I apply multivariate statistics and insect vision models to simulate how the pollinators perceive flower colors. This work is funded by the DAAD and CONICYT (Comisión Nacional de Investigación Científica y Tecnológica, Chile).