Indirect effects shape species fitness in coevolved mutualistic networks

Author(s)

Cosmo, Leandro G. ; Assis, Ana Paula A. ; de Aguiar, Marcus A. M. ; Pires, Mathias M. ; Valido, Alfredo ; Jordano, Pedro ; Thompson, John N. ; Bascompte, Jordi ; Guimaraes Jr, Paulo R.

• Document type: Journal article
• Source: Nature; v. N/A, p. 21-pg., 2023-07-19.

Abstract

Ecological interactions are one of the main forces that sustain Earth's biodiversity. A major challenge for studies of ecology and evolution is to determine how these interactions affect the fitness of species when we expand from studying isolated, pairwise interactions to include networks of interacting species(1-4). In networks, chains of effects caused by a range of species have an indirect effect on other species they do not interact with directly, potentially affecting the fitness outcomes of a variety of ecological interactions (such as mutualism)(5-7). Here we apply analytical techniques and numerical simulations to 186 empirical mutualistic networks and show how both direct and indirect effects alter the fitness of species coevolving in these networks. Although the fitness of species usually increased with the number of mutualistic partners, most of the fitness variation across species was driven by indirect effects. We found that these indirect effects prevent coevolving species from adapting to their mutualistic partners and to other sources of selection pressure in the environment, thereby decreasing their fitness. Such decreases are distributed in a predictable way within networks: peripheral species receive more indirect effects and experience higher reductions in fitness than central species. This topological effect was also evident when we analysed an empirical study of an invasion of pollination networks by honeybees. As honeybees became integrated as a central species within networks, they increased the contribution of indirect effects on several other species, reducing their fitness. Our study shows how and why indirect effects can govern the adaptive landscape of species-rich mutualistic assemblages. (AU)

• FAPESP's process: 21/14335-0 - ICTP South American Institute for Fundamental Research: a regional center for Theoretical Physics
• Grantee: Nathan Jacob Berkovits
• Support Opportunities: Special Projects
• FAPESP's process: 16/14277-2 - Genetic correlation's influence on coevolutionary processes
• Grantee: Ana Paula Aprígio Assis
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/22146-3 - How does differences in generation times affects coevolution in ecological networks?
• Grantee: Leandro Giacobelli Cosmo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/14809-0 - Evolutionary dynamics in ecological networks
• Grantee: Paulo Roberto Guimarães Junior
• Support Opportunities: Research Grants - Young Investigators Grants - Phase 2
• FAPESP's process: 19/25478-7 - Consequences of defaunation for plant diversity and ecosystem services in the Amazon Forest
• Grantee: Mathias Mistretta Pires
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/07939-0 - How does coevolution in mutualistic networks shapes discrete polymorphisms?
• Grantee: Leandro Giacobelli Cosmo
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate