Meeting Abstract
Vertebrate animals host a diverse community of internal and external parasites, the composition of which may interact with an individual’s immune functioning. Parasites of reptiles are particularly under-studied, and the interplay between parasites and immune functioning in reptiles is only beginning to be understood. We investigated the variation of parasitism by leeches and hemoparasites in two freshwater turtles, the midland painted turtle (Chrysemys picta marginata) and the northern map turtle (Graptemys geographica), in Ottawa County, Ohio in May-June 2017. We also assessed the relationship between leeches and shell algae. Finally, we investigated the relationships of parasitism and shell algae with the immune activity of turtles as measured by the skin-swelling response to a phytohemagglutinin challenge. The percentage of turtles infected with parasites (prevalence) and mean leech intensity (number of leeches) were similar for both turtle species, possibly because both species bask often and leeches may selectively choose hosts based on basking behavior. We detected a positive relationship between leech intensity and shell algae in painted turtles, but not map turtles. Infection status (i.e., parasitized by leeches only, hemoparasites only, both [co-infected], or neither), leech intensity and shell algae did not correlate with immune activity for either species. As a result of coevolution, the relationship between these parasites and their turtle hosts might currently be in a state of commensalism on the spectrum of symbiotic relationships. However, other measures besides immune activity, such as immunocompetence, are needed to fully assess the interactions between parasites and the complex immune system of turtles.
