Order: Testudinata Family: Chelydridae Chelydra serpentina Common Snapping Turtle.
Preferred Temperature, Metabolic Rate, and Circadian Rhythms of Snapping Turtles (Chelydra...
-
Upload
conrad-mcdaniel -
Category
Documents
-
view
217 -
download
0
Transcript of Preferred Temperature, Metabolic Rate, and Circadian Rhythms of Snapping Turtles (Chelydra...
Preferred Temperature, Metabolic Rate, and Circadian Rhythms
of Snapping Turtles (Chelydra serpentina)
Amy Pikovsky2004-05
Introduction
• My goals were to find:-Preferred temperature-Metabolic rate-Circadian rhythms-Correlations between the three variables
Background
• Snapping turtles are ectotherms• Ectotherms’ body temperatures are the same
as environmental temperatures
Importance
• Information about the effect of temperature on snapping turtles can be applied to all ectotherms.
• Snapping turtles are common, studies can then be applied to less common species
• Little research has been done about the interrelatedness of preferred temperature, metabolic rate, and circadian rhythms.
Previous Studies
• L.U. Williamson, et al. researched body temperature affects on metabolic rate in 1989
• K.B. and J.M. Storey researched the affect of very low temperatures on the metabolic rates of ectotherms in 1984
• A. Cortes et al. studied metabolic rates in diurnal and nocturnal ectotherms in 1994
Hypotheses
• Turtles will prefer higher temperatures with the lights on than with the lights off.
• Turtles’ metabolic rates will be higher at warm temperatures and lower at cold temperatures.
• Turtles’ metabolic rates will be higher with the lights on than with the lights off.
Materials
the temperature gradient
picture taken by author
• Initially, used T.V. and V.C.R. to find turtles’ positions
• Wrote LabView program to record positions in the gradient more easily
• Found corresponding temperatures• Used two procedures:
– 24 hour test in constant light– 48 hour test in constant light
Methods: Preferred Temperature
Methods: Metabolic Rate
• Set lights in the incubator to 14L:10D cycle
• Placed turtles in separate containers in incubator
• Measured CO2 production • Used Sable software to convert CO2
data into metabolic rate data
Methods: Circadian Rhythms
• Set lights in the gradient room to 14L:10D cycle
• Graphed temperature data• Looked for patterns
Results: Preferred Temperature
Descriptive statistics
Mean
(°C)
variance ave min T (°C)
ave max T (°C)
individual min (°C)
individual max (°C)
24 hr constant light
18.4 14.8 13.6 27.3 9.2 32.2
48 hr constant light
21.2 23 13.2 31.3 10 34.3
48 hr 14L:10D
18.4 10.8 13.9 25.7 9.7 34.1
5 10 15 20 25 300.00.10.20.30.40.50.6
Carbon dioxide produced (ml per hour)
B
temperature (degrees Celsius)
Mean resting metabolic rates of nine turtles at a variety of temperatures between 5.0 °C and 30.0 °C.
Results: Metabolic Rate
81012141618202224262830323436
Temperature ( degrees C)
Turtle 1 Turtle 2 Turtle 3
1:0013:00 13:00 1:00 13:00
Figure 1A: 48 Hours Turtles 1-3
Time
lights onlights offlights onlights on lights off
Selected temperatures of turtles 1, 2, and 3 during the first trial, 48 hour preferred temperature experiment in 14L:10D.
Results: Circadian Rhythms
81012141618202224262830323436
Temperature (degrees C)
Time
Turtle4 Turtle5 Turtle6
11:00 23:00 11:00 23:00 11:00
Figure 1B: 48 Hours Turtles 4-6 lights onlights offlights onlights on lights off
Selected temperatures of turtles 4, 5, and 6 during the second trial, 48 hour preferred temperature experiment in 14L:10D.
81012141618202224262830323436
Temperature (degrees C)
Time
Turtle 7 Turtle 8 Turtle 9
12:30 00:30 12:30 00:30 12:30
Figure 1C: 48 Hours Turtles 7-9lights onlights offlights onlights on lights off
Selected temperatures of turtles 7, 8, and 9 during the third trial, 48 hour preferred temperature experiment in 14L:10D.
101520253035
lights onlights offlights on
Temperature
Time13:00 1:00 13:00 1:00 13:00
lights on lights off
Mean of Trials 1A-1C
Mean selected temperatures of all nine turtles. Error bars show standard error.
Conclusions: Preferred Temperature
• Preferred temperatures were moderate (around 20 ºC) whether the lights were on or off
Conclusions: Metabolic Rate
• Metabolic rate and temperature were directly related: higher temperatures cause higher metabolic rates
Conclusions: Circadian Rhythms
• Some circadian patterns were evident: turtles moved more when the lights were on but the presence or absence of light did not affect temperature choice
Future Studies
• Research continues at the University of St. Thomas on:
Future Studies
• Research continues at the University of St. Thomas on:– Circadian rhythms of ectotherms
Future Studies
• Research continues at the University of St. Thomas on:– Circadian rhythms of ectotherms– Preferred temperature in the field
Significance
• Body temperature is very important to ectotherms
• Snapping turtles are common• Changes in weather and temperature
Acknowledgements
• Dr. Steyermark• Dr. Nelson• Anthony Giang• Students from Dr. Steyermark’s laboratory• Ms. Fruen• The research class
Preferred Temperature, Metabolic Rate, and Circadian Rhythms
of Snapping Turtles (Chelydra serpentina)
Amy Pikovsky2004-05