Epidemic size of different parasites in a single host species
Epidemic size—measured as the area under the infected host density curve during a single epidemic—varied by host species for P. ramosa (Fig. 5A, χ2 = 24.1, p < 0.001, df = 5) and B. paedophthorum (Fig. 5B, χ2 = 27.1, p < 0.001, df = 5). For P. ramosa , epidemics in D. dentifera and D. retrocurva were significantly larger than those in D. dubia and Ceriodaphnia (Conover–Iman, D.retrocurva-Ceriodaphnia p = 0.004, D. dentifera -Ceriodaphnia p < 0.001; Fig. 5B). ForB. paedophthorum , epidemics in D. dentifera and D. retrocurva were significantly larger than those in D. pulicaria(Conover–Iman, p < 0.001; Fig. 5B), and epidemics in D. dentifera were significantly larger than those in D. parvula(Conover–Iman, p = 0.02; Fig. 5B). Taken together with the centrality results, these results suggest host species differ in the degree to which they spread parasites to other host species.