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Author: Bailey Wallace
Author: Bailey Wallace
Introduction
Introduction
The Smooth Turtle Leech or Placobdella parasitica is a leech species native to the North Atlantic fresh waters of the Southeastern United States. It was first discovered by Thomas Say in 1824. The Smooth Turtle Leech is highly specialized aquatic worm related to the earthworm. It is a sanguinivore, meaning its diet consists of blood. It is an ectoparasite that mainly feeds off the Common Snapping Turtle, Chelydra serpentina, but has been found attached to a few other species of turtle and has been known to take opportunities with other prey like snails, fish, frogs, etc. It has a smooth dorsal surface that separates it from other Placobdella species. This description along with its diet mainly consisting of turtle blood is how this species got its common name.
Taxonomy:
Taxonomy:
Kingdom - Animalia
Phylum - Annelida
Class - Clitellada
Order - Rhyncobdellida
Family - Glossiphoniidae
Genus - Placobdella
Species - Placobdella parasitica
Photo by: Mark Siddall
Niche and Habitat
Niche and Habitat
P. parasitica can be found in many fresh water habitats like swamps, wetlands, ponds, lakes, etc. They use murky water, aquatic vegetation and other surroundings to hide from threats and predation from fish. Although aquatic, they are not very well equipped swimmers and spend most of their time on the bodies of turtles or on the bottom surface of the water body. Like most leeches, the Smooth Turtle Leech needs to maintain its moisture in order for it to avoid desiccation.
Since this species primarily drinks the blood of the Common Snapping Turtle, Chelydra serpentina, the habitats overlap. Because of this it is easier to show the distribution map of the Common Snapping Turtle (below) rather than that of the Smooth Turtle Leech due to insufficient data maps.
Evolutionary History
Evolutionary History
The Smooth Turtle Leech is a part of the annelida phylum and like all other annelids, its body is composed of rings or segments called annuli. The annelida phylum consists of invertebrates that are able to flex, stretch and bend their bodies because they have no spinal column. This is an advantage because they can get into small crevices of many types in the environment and on other animals' bodies.
Photo by: Dave Webb
Photo by: Dave Webb
The Smooth Turtle Leech has both anterior and posterior suckers that allow them move and explore. The movement is almost like an inch worm. They use the posterior sucker to anchor themselves to an object and explore with the anterior half before attaching it to another area and springing the rest of their body forward. A video of the movement is located below in the Website Links section.
The Smooth Turtle Leech uses the anterior sucker as a means to both anchor and consume the blood supply taken from the host. The anterior-most segments of the leech contain photoreceptors that act as eyes and send light signals to the leeches central nervous system.
Environmental Impacts
Environmental Impacts
There are no current concerns about this animals environmental impact. The only observation I have made is if the leeches somehow contracted and spread a disease to turtle populations causing them to become endangered. But no such disease has been recorded thus far.
Photo by: Dylan Winkler
Conservation
Conservation
There are no current concerns regarding the conservation of the Smooth Turtle Leech nor its main prey the Common Snapping Turtle. Both species are abundant and generally unharmed currently.
For centuries leeches have been bred and kept for medicinal uses. Before modern medicine, physicians and other medical professionals of the time used leeches in a practice called bloodletting. This practice was thought to help resolve flu-like symptoms such as fever. Bloodletting has since been revoked of any medicinal benefits but leeches are currently being used in other medicinal practices for hope of future solutions to health problems.
Friends or Foes?
Friends or Foes?
This species is the most common species of leech found on turtles all across North America and doesn't have to waste energy on competition for resources. Although many fish find them appetizing, no one fish has a hold on the population of these leeches. The host turtles it comes to prey on have more than enough blood supply for the leech to survive and breed from. The only foe or disadvantage this leech may have is from turtles that like to surface and sunbathe. Sunbathing is a superpower for turtles that can kill or get rid of leeches by exposing them to desiccation.
Videos of Placobdella parasitica
Videos of Placobdella parasitica
Web Resources for Audience to Explore
Web Resources for Audience to Explore
This webpage briefly describes P. parasitica and reports a study done by the Phinizy Center for Water Sciences. The study recounts the amount of P. parasitica found on the Yellow-Bellied slider (Trachemys scripta scripta), common snapping turtle (Chelydra serpentina) and musk turtles (Sternotherus odoratus).
Parasite of the Day Blog: Placobdella parasitica
This blog has hundreds of entries on parasites! This particular entry describes Placobdella parasitica’s reproduction habits and how it’s young start their lives.
This link defines what a photoreceptor is so that the audience can understand how leeches and many other animals are able to see and navigate their world.
iNaturalist - Placobdella parasitica
It also gives an overview, map distribution of observations and taxonomic details about different species. It is a public interface that the general public can use to identify pictures of different species.
This blog describes how in the Francis Beidler Forest turtles are often parasitized by leeches. It gives a good description of one defense that sunbathing turtles have against these leeches; the sun. The sun desiccates the leeches either until they drop off or until they parish.
Variety of Placobdella parasitica Images
This web page gives the viewer an assortment of very detailed images of the Smooth Turtle Leech species. In these photos you can clearly see the size and segments of the leeches body.
Resources
Resources
Melton, Robert. (2015). “The Turtle Leech.” Edited by Camilla Sherman, Phinizy Center for Water Sciences, phinizycenter.org/turtle-leech/.
“Placobdella Parasitica.” (N.A.) Maryland Biodiversity Project, www.marylandbiodiversity.com/view/5073&showAll=1.
“Placobdella Parasitica (Say, 1824).” (N.A.). WoRMS - World Register of Marine Species, www.marinespecies.org/aphia.php?p=taxdetails&id=1436331.
Shelley, Rowland. (1977). “North Carolina’s Terrestrial Leech”. Wildlife in North Carolina. Vol. 41, Issue 9
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