Structural colors in fruits
Most plant colors are derived from pigments such as anthocyanins or carotenoids, but occasionally plants evolve nanostructures that interfere with light to produce color. Such colors derived from the physical interaction of light with matter are called structural colors, and in fruits we are continually finding more and more species that exhibit such nanostructures, built out of lipids embedded in the cell wall. In Viburnum, the use of lipids to create blue fruit color is associated with a lipid-rich nutritional content, raising the possibility that the color is an honest signal of fruit nutrition. The ecological consequences of using lipids to make color are potentially numerous, and I am particularly interested in delving into the ecological functions of structural colors, especially as we discover more and more species using different chemistries, different structures, in different locations.
Macroecological patterns in fruit traits
Historically, fruit colors have been thought to evolve primarily in response to selection by animal dispersers, with bird and mammal dispersers selecting for distinct suites of traits. However, there is equally strong reason to believe that environmental factors such as temperature, precipitation, or light environment may have a strong impact on fruit color diversity and evolution. We now know that fruit color varies across latitude, that temperature and disperser diversity interact to influence global spatial patterns in fruit colors, and that flower and fruit color diversity are negatively associated across clades. Such findings suggest that the factors that influence fruits may vary across space and biological scale.
Lantana
Lantana strigocamara (syn. L. camara) is a highly invasive weed in tropical regions throughout the world, and it uses structural color to produce its blue, metallic fruit color. I am working to build L. strigocamara as a model system for several aims, including 1) addressing the evolutionary origins of structural color in the fruits, and 2) the role of fruit coloration in influencing seed dispersal. L. strigocamara is also closely related to L. depressa, and endangered species in south Florida, with which it regularly hybridizes. Furthermore, the phylogeny of Lantana sect. Lantana is complex with — likely — many hybridization events. Consequently, my collaborators (chiefly, Pat Lu-Irving) and I are interested in improving our understanding of the phylogeny of the Lantaneae, developing genomics resources within this lineage, and using those resources to better understand the evolution of color within the group, along with why and how L. strigocamara is such a successful weed.
