Map Turtle Winter Leech Loads

Abstract

Adult common map turtles, Graptemys geographica (n = 243), were obtained in November 1995 from a hibernation site in the Lamoille River, Vermont. Of the 208 female turtles examined, 151 (72.6%) had at least 1 leech (Placobdella parasitica) attached and 10 of 35 males (28.6%) were similarly parasitized. Mean abundances were 1.49 (SD = 1.461, n = 208) for female turtles and 0.34 (SD = 0.591, n = 35) for males; the difference was significant (t = 4.558, df = 241, P < 0.001). Leech broods were found on 34 of 208 female turtles (16.3%) and 2 of 35 males (5.7%). One of the leeches was of record size (77.7 mm total length); another specimen measuring 64.4 mm had 153 brood-sized (x = 4.5 mm) young attached to its venter. Because of poor visibility and partial ice cover, only 7 turtles were recovered in March 1996. All of these turtles had attached leeches, and 4 turtles had broods of 9-52 young ranging in length from 4.58 to 5.78 mm. One Placobdella ornata was found in the March sample. Our results suggest that leeches of various size classes remain attached to hibernating adult map turtles throughout the winter.