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Research Interests

PicturePhoto by Ellen Woods
Our research lies at the nexus of ecology and evolutionary biology, linking species interactions at the ecological scale with phenotypic evolution and diversification at the macroevolutionary scale. 

Understanding the role that ecological interactions have played in shaping the evolution of biodiversity on our planet is a major goal in biology. However, because of the large scale of processes at play, elucidating links between species interactions and broad-scale evolutionary patterns has remained a challenge. Research in the Weber Lab takes an integrative approach to asking how species interactions have impacted the striking diversity found across the tree of life. We focus on mutualistic and defensive interactions between plants and animals as model systems, testing hypotheses that link ecological mechanism to evolutionary pattern. Our work integrates a diverse set of approaches including comparative phylogenetics, community & chemical ecology, microbiome community sequencing,  genomics, and manipulative field experiments. Check out our publications for more details!

Here are some of the major topics we study in the lab:

​1: The role of ecological interactions in the generation and maintenance of biodiversity: ​
Across the tree of life, some groups of species have undergone extensive phenotypic innovation and lineage diversification, while others have not. Why some branches on the tree of life flourish, and others flounder, remains an unanswered question in evolutionary biology. Much of our work focuses on elucidating the role that ecological interactions have played in driving variation in speciation and extinction rates across phylogenies, focusing on the role of phenotypes that mediate plant-animal interactions.
Example publications: 
​
Foisy, M.R., Albert, L.P., Hughes, D.W.W., and M.G. Weber. 2019. Do latex and resin spur diversification? Reexamining an early hypothesis of escape and radiate coevolution. Journal of Ecology. 107(4) 1606-1619.

Weber, M.G. and A. A. Agrawal, 2014. Defense mutualisms enhance lineage diversification in plants.  Proceedings of the National Academy of Science. 111(46), 16442-16447.

Chomicki, G., Weber, M.G., Antonelli, A., Bascompte, J., and T. Kiers. 2019. The Impact of Mutualisms on species richness. Trends in Ecology and Evolution. 34(8) 698-711.
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Harmon, L., C., Andreazzi, C., Drury, J.P., Goldberg, E., Martins, A., Melián, C., Narwani, A., Pennell, M., Rudman, S., Seehausen, O., Silvestro, D., Weber, M.G. and B. Matthews. 2019. Detecting the Macroevolutionary Signal of Species Interactions. Journal of Evolutionary Biology. 32(8) 769-782.

Weber, M.G., and A.A. Agrawal. 2012. Phylogeny, ecology, and the coupling of comparative and experimental approaches. Trends in Ecology and Evolution 27: 394-403.
2. Historical trait evolution and the coexistence of closely related species in contemporary communities: 
 Ever since Darwin, biologists have puzzled over the mystery of how closely related species, which are similar due to common descent, can coexist with one another in time and space. A major branch of our research investigates fundamental questions about the role of phenotypic evolution in contemporary coexistence of closely related species. To make these links, we apply comparative phylogenetic modeling, large-scale phenotyping, and range reconstruction to classic plant-pollinator interactions as model systems. 
Example publications: 
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Weber, M.G., Mitko, L., Eltz, T., and S.R. Ramírez. 2016.  Macroevolution of perfume signaling in orchid bees. Ecology Letters. 19 (11), 1314-1323.
 
Weber, M.G., N.I. Cacho, M.J.Q. Phan, C. Disbrow, S.R. Ramírez, S.Y. Strauss. 2018. The evolution of floral signals in relation to range overlap in a clade of California Jewelflowers (Streptanthus s.l.). Evolution. 72(4), 798-807.

Weber, M.G., Wagner, C. E., Best, R.J., Harmon, L.J., and B. Matthews. 2017. Evolution in a community context: on integrating ecological interactions into macroevolution. Trends in Ecology and Evolution. 32(4): 291-304.

Weber, M.G., and S.Y. Strauss. 2016. Coexistence in close relatives: Beyond competition and reproductive isolation in sister taxa. Annual Review of Ecology, Evolution, and Systematics. 47 (1). 359-381.​

 3. Linking ecology and evolution via the study of plant defense: 

Traits that defend species from natural enemies are pervasive, have originated independently many times, and are highly variable across taxa. We are broadly interested in understanding how the evolution of plant defense traits is impacted by different environmental, historical, and biotic factors, as well as the consequences of evolutionary changes in these phenotypes for the interactions they mediate. Because these phenotypes are heritable and function almost exclusively in mediating ecological defensive interactions with animals, they are ideal models for connecting evolutionary change to ecological function. Defensive traits provide beautiful natural experiments with which to ask questions about the evolutionary ecology of plant-animal interactions at varying scales - from the mechanisms of trait function and impacts on plant fitness, to the patterns of deep-time trait evolution. This work is not only important for illuminating our understanding of how evolution operates, but also informs solutions to the growing humanitarian crisis of feeding the world’s growing human population.
Example publications: 

Weber, M.G., Porturas, L.D., and S.A. Taylor. 2016. Foliar nectar enhances plant-mite mutualisms: The effect of leaf sugar on the control of powdery mildew by domatia-inhabiting mites. Annals of Botany. 118(3), 459-466.

Weber, M.G., and K.H. Keeler. 2013. The phylogenetic distribution of extrafloral nectaries in plants. Annals of Botany. 111 (6): 1251-1261.

Weber, M.G., Clement, W.L., Donoghue, M.J., and A.A. Agrawal. 2012. Phylogenetic and experimental tests of interactions among mutualistic plant defense traits in Viburnum (Adoxaceae). 

LoPresti, E.F., Pan, V., Goidell, J., Weber, M.G., and R. Karban. 2019. Mucilage-bound sand reduces seed predation but not by reducing apparency; a field test of 53 plant species. Ecology. e02809.