Editor’s Choice section of Science (vol. 333: 1201) this week includes a comment by Andrew Sudgen on our recent paper just published in Ecology Letters. The comment highlights the innovative aspects of studying multispecific coevolution and developing the first model to address the consequences of diversified interactions within complex mutualistic networks.
Just appeared in the Sept issue of Ecol. Lett. A major current challenge in evolutionary biology is to understand how networks of interacting species shape the coevolutionary process. We combined a model for trait evolution with data for twenty plant-animal assemblages to explore coevolution in mutualistic networks. The results revealed three fundamental aspects of coevolution in species-rich mutualisms. First, coevolution shapes species traits throughout mutualistic networks by speeding up the overall rate of evolution. Second, coevolution results in higher trait complementarity in interacting partners and trait convergence in species in the same trophic level. Third, convergence is higher in the presence of super-generalists, which are species that interact with multiple groups of species. We predict that worldwide shifts in the occurrence of super-generalists will alter how coevolution shapes webs of interacting species. Introduced species such as honeybees will favour trait convergence in invaded communities, whereas the loss of large frugivores will lead to increased trait dissimilarity in tropical ecosystems.
This is a first attempt to get to models of how coevolved changes might drive the evolution of highly diversified networks of ecological interactions. Each of the interactions that we can map in these networks really represents a set of reciprocal selection forces deriving from the interaction itself. Up to know we were lacking a general theory of how coevolution can proceed in these diversified assemblages, given that these natural selection forces remain diversified, asymmetric and, generally, weak. We show that strictly coevolved changes might in fact be scarce in this scenario, but they trigger cascades of changes that significantly contribute to the evolving network. The work stems on my ongoing collaboration with Paulo R. Guimarães and John N. Thompson, and the excellent work Paulo developed during his postdoc stay in Sta Cruz at John’s lab.
Fruits show an immense diversity of colors and displays. However, we are still far from a general theory for the evolution of fruit displays. The main elements of those displays do not only include color itself, but also characteristics of the fruit “design” (ow the fruit is built) like number of seeds, amount of pulp, size, etc., and the nutrients in the pulp (both macro- and micro-nutrients, as well as secondary compounds). All this adds an extraordinary complexity and diversity to the fruit displays. Together with Alfredo Valido and Martin Schaefer I’ve been exploring the evolutionary patterns of fruit traits for the Iberian Peninsula fleshy-fruited flora (ca. 120 species). We studied whether correlated trends between these elements of the display (design, nutrients, color) have been maintained through the phylogenetic diversification of the flora. We found some interesting patterns of covariation between sugar content, lipid content, and color that suggest predictable patterns of fruit evolution in relation to the main types of frugivores feeding on the fruits. Our results suggest that the evolution of fruit displays has been quite constrained by history, yet selection by frugivores might have contributed to marked and predictable covariation among color and nutrient contents. This is an interesting finding to understand the evolution of visual signals in plants, acting to attract diverse suites of animal frugivores that can act as legitimate dispersers of the seeds. Our work is now in press in Journal of Evolutionary Biology.
Our review on seed dispersal effectiveness just published in New Phytologist: “Just appeared in the last issue of New Phytologist: our paper ‘Seed dispersal effectiveness revisited: a conceptual review’ [DOI: 10.1111/j.1469-8137.2010.03402.x], co-authored by Eugene W. Schupp, myself, and José M. Gómez. This has been a nice project and a timely review (after 17 years of Geno’s classic paper) on dispersal effectiveness. We expand the concept and review what we know and what we don’t know, suggesting new ideas for future research.”
(Via Weblog de Pedro.)
5th Annual Harvard Plant Biology Symposium Plants and the evolution of cooperation & trading: “Just arrived from the Harvard Univ. symposium,dedicated this year to mutualisms and the evolution of coorperation. Very interesting inter-disciplinary meeting with ecologists, economists, etc. and nicely setup by Naomi Pierce’s lab. My talk was about: ‘Complex networks of interactions and their consequences in diversified plant-animal mutualisms’.”
(Via Weblog de Pedro.)
We have just published our paper “Olesen, J.M., Bascompte, J., Dupont, Y., and Jordano, P. 2007. The modularity of pollination networks. Proceedings of the National Academy of Sciences USA, 104: 19891-19896”. These are great news since it represents a very nice work lead by Jens. Here we relate the concept of moodularity to our previous work on nestedness in mutualistic plant-animal assemblages.
New paper in Nature
Three days ago we had the good news of our manuscript on coextinction cascades in plant-animal mutualistic networks being finally accepted in Nature. These are very good news for the group, especially for our efforts in the last 4 years working on complex webs of interactions. Enrico did a superb job leading this ms. Here is the abstract:
Rezende, E., Lavabre, J., Guimarães Jr., P.R., Jordano, P. and Bascompte, J. 2007. Non-random coextinctions in phylogenetically structured mutualistic networks. Nature 00: 000-000.
The interactions between plants and their animal pollinators and seed dispersers have molded much of Earth’s biodiversity. Recently, it has been shown that these mutually beneficial interactions form complex networks with a well-defined architecture that may contribute to biodiversity persistence. Little is known, however, about which ecological, evolutionary, and coevolutionary mechanisms contribute to generate these network patterns. Employing phylogenetic comparative statistical tools, here we show that the evolutionary history of plants and animals significantly predicts the number of interactions per species, and the identity of the species with whom they interact. As a consequence of phylogenetic resemblance on interaction patterns, simulated extinction events tend to trigger coextinction cascades across related species. This results on a non-random pruning of the evolutionary tree and a more pronounced loss of taxonomic diversity than expected in the absence of phylogenetic signal. Our results emphasize how the simultaneous consideration of phylogenetic information and network architecture can contribute to the conservation of species rich communities.
Photos of megafauna fruits
Go here if you want a view of megafauna fruits photos . These were taken by Mauro Galetti and me at the Museo Goeldi Herbarium (Belem, Brazil) and correspond to species we analyzed in our ongoing project on megafauna fruits.