Modelling coevolution in ecological networks with adaptive dynamics

Abstract

MOS Classification: 92D40; 47J35; 91A22 Communicator: R. Anguelov Coevolution can impose density-dependent selection through reciprocal biotic interactions on the fitness of involved species, driving directional and disruptive trait evolution and rich evolutionary possibilities. Coevolution has since Darwin been considered a potential path leading to adaptive diversification that could explain the emergence of ecological networks of biotic interactions that harbour multiple interacting species (eg, pollination networks and food webs). Here, we present adaptive dynamics, a powerful tool of evolutionary invasion analysis that explores how quantitative traits undergo incremental evolution, to exploring the emergence of multi-species networks through coevolution. Specifically, we exemplify the feasibility of using adaptive dynamics to investigate trait evolution in 4 ecological networks, driven, respectively, by resource competition, trophic interactions, as well as bipartite mutualistic and antagonistic interactions. We use a set of ordinary differential equations to describe, at different paces, the population dynamics and trait dynamics of involved species assemblages. Through computing ecological equilibrium, invasion fitness, selection gradient and evolutionary singularity, and testing for evolutionary stability and the coexistence criterion of mutual invasibility, we illustrate the typical evolutionary dynamics and the criteria of evolutionary stability and branching in these ecological networks. Results highlight the importance of the form of trait-mediated interaction kernel (ie, interaction strength as a function of trait difference) to adaptive diversification in these coevolutionary systems. We conclude by advocating that biotic interactions between two species can indeed lead to diffuse and even escape-and-radiate coevolution, making the emerged ecological networks an ideal model for studying complex adaptive systems. KEYWORDSadaptive dynamics, complex adaptive networks, ecological networks, evolutionary branching, evolutionary invasion analysis, evolutionary stability

Complexity and stability of ecological networks: a review of the theory

“…Trait adaptation can also be modelled and give rise to complex trophic interaction networks (Brännström et al 2011(Brännström et al , 2012Landi et al 2013Landi et al , 2015Hui et al 2018), and their complexity-stability relationship assessed (Kondoh 2007;Ingram et al 2009). In particular, Kondoh (2007) studied adaptation in predator-specific defence traits, reporting its unimodal effect on the complexity-stability (connectance-persistence and robustness) relationship, while species richness always has a negative impact on stability.…”

The geographic mosaic of coevolution in mutualistic networks

“…For mutualisms, previous studies have explored how coevolution may affect network architecture-that is, the pattern of interactions among species-and, in turn, how such architecture may drive coevolution. The role of coevolution in shaping the organization of links of empirical networks is still uncertain (9)(10)(11)(12). Nevertheless, it is known that network architecture varies with fundamental aspects of the natural history of interactions, potentially leading to distinct coevolutionary dynamics (7,13).…”

Effects of phylogeny on coexistence in model communities

“…One would then take the sub-tree of that community as the starting point for the new speciation event. In this setting, in a similar manner to studies of community assembly [32] and the framework of adaptive dynamics [21], we have a separation of time-scales between the speciation events and the local community dynamics. Traits evolve on the tree between each pruning event.…”