PREVALENCE OF INTRAERYTHROCYTIC PARASITES IN MAROCHELYS TEMMINCKII, EMYDOIDEA BLANDINGII, TERRAPENE CAROLINA CAROLINA, AND TERRAPENE ORNATA ORNATA

Few studies have characterized the prevalence of intraerythrocytic parasites in free-ranging chelonian populations or their occurrence across habitats. It is hypothesized that chelonians in different habitats have different exposures to vectors and thus, differences in hemoparasite presence. This study explored the prevalence and intensity of intraerythrocytic parasites by examining blood smears from four species of Illinois turtles: wild Blanding’s turtles (Emydoidea blandingii), eastern box turtles (Terrapene carolina carolina) (EBT), and ornate box turtles (Terrapene ornata ornata) (OBT) and headstarted alligator snapping turtles (Macrochelys temminckii) (AST). Intraerythrocytic parasites were identified in all examined species except for the alligator snapping turtle. For all age classes, Blanding’s turtles had both the highest prevalence of hemoparasites and intensity of infection of all sampled species, while adult Blanding’s turtles had a significantly higher prevalence than juveniles (P<0.05). As this is the first study of hemoparasites in Illinois chelonians, further research is needed to identify the specific species of intraerythrocytic parasite, the potential vectors, and the effect these hemoparasites have on the health of chelonians.

A Dynamic Energy Budget Model of Ornate Box Turtle Shell Growth

Many aspects of box turtle development may depend on size rather than age. Notable examples include sexual maturity and the development of the fully closing hinge in the shell that allows box turtles to completely hide in their shells. Thus, it is important to understand how turtles grow in order to have a complete understanding of turtle biology. Previous studies show that turtle shell growth behaves in a logistic manner. These studies use functional models that fit the data well but do little to explain mechanisms. In this work we use the ideas found in dynamic energy budget theory to build a model of box turtle shell growth. We show this model fits the data as well as previous models for ornate box turtles Terrapene ornata ornata, but also offers explanations for observed phenomena, such as maximum sizes and the appearance of biphasic growth.

Thermal consequences of subterranean nesting behavior in a prairie-dwelling turtle, the Ornate Box Turtle (Terrapene ornata)

Many oviparous reptiles deposit eggs in excavated nest chambers, and the location and depth at which eggs are laid can affect predation risk, incubation duration, mortality rates, and hatchling phenotype. Among turtles, nest depth also influences incubation conditions of some large-bodied species, but nest depth is generally expected to vary less among small-bodied species. We monitored nesting behavior of Ornate Box Turtles (Terrapene ornata (Agassiz, 1857)) for two seasons in Illinois. We used direct observations to confirm that, among 31 nesting events, six females oviposited while beneath the substrate surface. Furthermore, comparisons of body length to nest depth indicated that five additional females likely also constructed nests while buried. Nests laid while females were underground were deeper, on average, than other nests (16.7 versus 11.2 cm), and while mean nest temperatures were similar between groups, temperature fluctuations and maximum temperatures were lower among nests that were laid while females were underground. Subterranean oviposition appears to have moderated incubation temperatures by allowing females to deposit eggs at greater depths than would be possible from the surface. This little-documented behavior may be a mechanism for this species to influence the incubation environment, which in turn may influence hatchling phenotypes.