Supporting experimental evidence of host specificity among southern African polystomes (Polystomatidae:Monogenea).

Although monogeneans of anurans are generally regarded as host-specific, there is a lack of conclusive experimental evidence. Infection and cross-infection experiments were conducted with oncomiracidia of Polystoma australis and P. marmorati. In a series of experiments, oncomiracidia were given a choice between natural and substitute host tadpoles. Oncomiracidia of P. australis became established in substitute hosts but showed a preference for the natural host, whereas the oncomiracidia of P. marmorati showed a strong and statistically significant preference for the natural host. The results indicated that although the oncomiracidia of southern African polystomes showed a strong preference for their natural hosts, not all parasites exercised the same degree of host specificity.