Abundance-prevalence relationship of gill congeneric ectoparasites: testing the core satellite hypothesis and ecological specialisation.

We investigated the abundance-prevalence relationships in monogeneans belonging to the genus Dactylogyrus. A total of 182 dactylogyrid populations representing nine species were collected from the gills of roach ( Rutilus rutilus). Local abundance was found to be strongly positively correlated with prevalence. Two hypotheses were tested to explain this relationship: (1) the core-satellite hypothesis, and (2) the ecological specialisation hypothesis. Abundance was log-normally distributed, and the relationship between mean abundance and variance of abundance followed Taylor's power law prediction. Prevalence showed a negative binomial distribution, which does not confirm the core-satellite hypothesis. The positive relationship between abundance and prevalence was found for both specialists and generalists. However, generalists were found to be more widely distributed among hosts and had higher abundances than specialists, which supports the ecological specialisation hypothesis.