Author

Ben Anders

Date of Graduation

Summer 2008

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Don Moll

Keywords

Trachemys, ultraviolet light, laterality, righting response, chelydra, biomass

Subject Categories

Biology

Abstract

Turtles are exposed to UV-B rays through basking, and since vitamin D3 is essential to the uptake of dietary calcium, UV-B light is considered important for growth in these animals. I studied the effects of UV-B light bulbs on growth in slider turtles (Trachemys scripta: N = 243) from hatching to eight months of age. Growth was defined as the difference between initial and final carapace length and mass and was analyzed against treatment and row via analyses of variance (ANOVA). A significant effect from row (and presumably temperature) was found, but turtles had similar growth regardless of UV-B treatment. Many species of turtles have keeled carapaces that cause a left or right lateral tilt upon inversion on land. I investigated the righting response in slider turtles (Trachemys scripta: N = 102) to see whether choice of pivot side is correlated with inversion tilt. In 100% of trials, inverted turtles pivoted to the same side as the inversion tilt. Use of the carapacial keel to achieve maximum difference between costs and benefits in the righting response supports a hypothesis of the keel serving an important terrestrial function in an aquatic turtle species. Aquatic turtles were trapped in a South Creek impoundment at Darr Agricultural Center from June to July of 2007. One hundred twenty-six turtles (six species) weighed a total of 189.03 kg, the most abundant of which were slider turtles (Trachemys scripta) (64% total specimens, 33% total mass) and snapping turtles (Chelydra serpentina) (28% total specimens, 63% total mass). These data suggest that the turtle community contributes a significant proportion of the stream's biomass and imply that its ecological role within this greatly altered ecosystem is of considerable importance.

Copyright

© Ben Anders

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