Host-breadth and cross-species transmission connections in different parasite species networks
All parasite-specific measures—host breadth, cross-species transmission connections, and graph density—suggest parasites in these communities vary in their ability to infect and transmit between different host species (Fig. 3). Each of these three measures showed significant differences among parasite species (Kruskal–Wallis test, p < 0.001 for all: see Figure 3 legend for individual tests), and the median values and pairwise comparisons were largely the same across metrics. B. paedophthorum, S. cienkowskii, and P. ramosa were always infective to the most host species, with our analysis indicating that they infect approximately the same number of host species. Of these three parasite species, B. paedophthorum , in particular, had consistently higher values compared to the four lower scoring parasite species (i.e., M. bicuspidata , L. obtusa ,G. vavrai , and ‘Spider’), suggesting it is more of a multihost parasite than the others.
Comparing host breadth (Fig. 3A) and cross-species transmission connections (Fig. 3B) provides information that combined graph density (Fig. 3C) does not. For instance, B. paedophthorum is the only parasite species that was found in every host species at one of the sites (and, at one site with 4 hosts, all host species were infected; host breadth = 1). Also, while G. vavrai was found to infect multiple host species, those epidemics never overlapped in time and space (Fig. 3B, values = 0). However, overall, parasite species that had higher host breadth also tended to have more overlapping epidemics across host species.