OCCURRENCE OF PLACOBDELLA-PARASITICA (HIRUDINEA) ON SNAPPING TURTLES, CHELYDRA-SERPENTINA, IN SOUTHEASTERN ONTARIO

During the summers of 1987-1989, we recorded prevalence, intensity, and site of occurrence of leeches (Placobdella spp.) on snapping turtles (Chelydra serpentina) in Algonquin Park, Ontario. Placobdella parasitica was the most common species found, accounting for 96% of 829 specimens identified on Chelydra in 1988 and 1989. The remaining 4% were Placobdella ornata. Male turtles had more clusters of leeches than did female turtles, but there was no difference between sexes in the number of solitary leeches ≥ 1 cm in length. Number of clusters of leeches was correlated positively with mass of the turtle, but there was no correlation between the number of solitary leeches ≥ 1 cm and turtle mass, or between the number of solitary leeches and clusters. Both clusters and solitary leeches ≥ 1 cm occurred significantly more often on the posterior region of the turtles than on other, more exposed, areas. Size of clusters and numbers of solitary leeches found on the turtles were much higher than reported previously. Our results indicate that basking is not effective in removing leeches and that both intensity and size of leeches are positively related to the size of the turtle host.