Network analysis of host–virus communities in bats and rodents reveals determinants of cross-species transmission

Luis, Angela D.; O'Shea, Thomas J.; Hayman, David T. S.; Wood, James L. N.; Cunningham, Andrew A.; Gilbert, Amy T.; Mills, James N.; Webb, Colleen T.

We calculated various node and network statistics ( Table 1 ). The node statistics that we calculated were degree (the number of links a node has), weighted degree (incorporating the number of viruses shared) and betweenness (the number of shortest paths that go through a node (weighted)). The network statistics that we calculated included the degree distribution, transitivity (if two nodes are connected, the probability that their adjacent nodes are also connected), degree assortativity (likelihood of high-degree nodes connecting to other high-degree degree nodes and low-degree nodes to other low-degree nodes) and connectance (links per species 2 , or the proportion of links that are present out of all possible links). We also calculated quantitative connectance, which is the quantitative linkage density (which takes into account the weights of the edges; Bersier et al. 2002) divided by the number of species in the network.