Table 2.

Variables used to predict parasite acquisition. For trait.diff.mean and trait.diff.min, ‘host trait scores’ come from a principal component analysis of PanTHERIA, a database of mammal traits ([48]; see the electronic supplementary material for details).

category	predictor	description
characteristics of parasites	ParType	parasite taxonomic group: arthropod, bacteria, helminth, protozoa or virus
	close, nonclose, vector, intermediate	parasite transmission mode(s), each scored separately as a binary variable
	n.modes	parasite's number of transmission modes
	prev.mean, prev.max	mean and maximum parasite prevalence across infected hosts in the non-native range, excluding the focal host
	n.hosts	number of non-focal hosts in which the parasite was found in a focal host's non-native range
	all.hosts	number of known mammal hosts per parasite across all GMPD records, excluding the focal host
	z.score	standardized measurement of a parasite's phylogenetic range breadth; negative values indicate greater degree of host specialism
characteristics of parasites’ hosts	PD.mean, PD.min	mean and minimum pairwise phylogenetic distances between a parasite's hosts (those tallied in n.hosts) and the relevant focal host; units are millions of years ago (Ma)
	trait.diff.mean, trait.diff.min	mean and minimum difference in host trait scores between a parasite's hosts (those tallied in n.hosts) and the relevant focal host