Prevalence of Aeromonas hydrophila in relation to timing and duration of breeding in three species of ranid frogs

Abstract

:Species of temperate ranid frogs differ in ways (e.g., habitat preferences, timing and duration of their breeding seasons) that could influence their susceptibility to parasites and pathogens. In this study, we compared the prevalence of Aeromonas hydrophila in breeding adults of bull frogs (Rana catesbeiana), green frogs (R. clamitans), and leopard frogs (R. pipiens) from a region in eastern Ontario. Adult R. pipiens had a higher prevalence of A. hydrophila than either R. clamitans or R. catesbeiana, but there were no differences between sexes. There was also a trend for a decline in prevalence of A. hydrophila over the breeding seasons of all three species. Reduced immune ability soon after emergence from hibernation could explain the higher prevalence of A. hydrophila earlier in the season. The higher prevalence in R. pipiens may be a function of earlier and contracted breeding in this species. The expected high stress during breeding for this species could have implications for its relative susceptibility to other disease agents that share routes of infection with A. hydrophila or that are challenged by the same components of the immune system.