Network Spandrels

Biological networks show strong departures from simple models of random graphs. For example, they display broader degree distributions, high modularity, and strong preponderance of certain motifs.

One might be tempted to interpret these features as a signal of a selective force pruning the space of possible networks, resulting in empirical networks possessing certain features.

In one of my all-time favorite papers, Ricard Solé & Sergi Valverde proposed an alternative explanation: these features might be by-products of how the network was assembled. They dubbed this the “network-spandrel” hypothesis, referencing the famous paper by Gould & Lewontin.

In a new paper just published in Ecology Letters, Dan Maynard, Carlos Serván and I show a simple model of ecological assembly where by slightly tweaking the rules of assembly we can obtain dramatically different network structures—a paradigmatic case of network spandrels:

Daniel S. Maynard, Carlos A. Serván & Stefano Allesina
Network spandrels reflect ecological assembly
Ecology Letters, 2018

Notably, the idea of network spandrels will be the focus of a Satellite Session at NetSci 2018 in Paris. The satellite is being organized by many of the current and past collaborators of the lab.