EPIZOIC ORGANISMS ON TURTLES IN SELECTED HABITATS OF THE UPPER MISSISSIPPI 
RIVER.

Cathy L. Ziglar and Richard V. Anderson
Department of Biological Sciences, Western Illinois University, 1 University 
Circle, Macomb, IL  61455

While it has long been recognized that turtles harbor a large number of 
epizoites few studies have looked at the epizoic community as a whole or 
compared the epizoites of turtles in different habitats.  Turtles were collected 
from 3 habitats; open river, slough, and backwater, in the upper reach of Pool 
20, Mississippi River.  One hundred thirty-nine turtles of 6 species were 
examined for epizoites, but only red-eared sliders, (Trachemys scripta), common 
snapping turtle (Chelydra serpentine), painted turtles (Chrysemys scripta) and 
soft-shelled turtles (Apolone spp.) were collected in sufficient numbers for 
data analysis.  Five epizoites were attached directly to turtles; 3 species of 
leeches of genus Placobdella, algae of genus Basicladia, and protozoan 
Vorticella.  All hard shelled turtle species carried all 5 epizoites, but soft-
shelled species carried only P. multilineata, P. ornata, and Vorticella.  The 
highest infestation rates occurred on snapping turtles with 94% leeches, 94% 
algae, 48% Vorticella.  The lowest rates for each group of epizoites were 
painted turtles with 26% leeches, and soft-shelled turtles with 0% algae, and 5% 
Vorticella.  Habitat specificity was found for the leech, P. ornata, and 
Vorticella both of which occurred significantly more frequently on snapping 
turtles and red-eared sliders in the backwater habitat.

Keywords: Mississippi River, Pool 20, habitats, freshwater turtles, epizoites,