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.