ORIGINAL PAPER Trait-mediated interaction leads to structural emergence in mutualistic networks H. O. Minoarivelo 1 • C. Hui 1,2 Received: 18 May 2015 / Accepted: 31 August 2015 / Published online: 5 September 2015 Ó Springer International Publishing Switzerland 2015 Abstract As asymmetric structures of mutualistic networks can potentially contribute to system resilience, elucidating drivers behind the emergence of particular network archi- tectures remains a major endeavour in ecology. Here, using an eco-evolutionary model for bipartite mutualistic networks with trait-mediated interactions, we explore how particular levels of connectance, nestedness and modularity are affected by three network assembly forces: resource accessibility, tolerance to trait difference between mutualistic pairs and competition intensity. We found that a moderate accessibility to intra-trophic resources and cross-trophic mutualistic support can result in a highly nested web, while low tolerance to trait difference between interacting pairs leads to a high level of modularity. Network-level trait complementarity leads to low connectance and high modularity, while network-level specialization can result in nested structures. Consequently, we argue that the interplay of ecological and evolutionary processes through trait-mediated interactions can explain these widely observed architectures in mutualistic networks. Keywords Network architecture  Nestedness  Connectance  Compartmentalization  Modularity  Trait complementarity  Network specialization Electronic supplementary material The online version of this article (doi:10.1007/s10682-015-9798-z) contains supplementary material, which is available to authorized users. & C. Hui chui@sun.ac.za 1 Department of Mathematical Sciences, Centre for Invasion Biology, Stellenbosch University, Matieland 7602, South Africa 2 Mathematical and Physical Biosciences, African Institute for Mathematical Sciences, Cape Town 7945, South Africa 123 Evol Ecol (2016) 30:105–121 DOI 10.1007/s10682-015-9798-z