1. The Effects of Light Cycle on Metamorphosis in Salamanders Kenn Rose 1,2 and Christopher K. Beachy 1 1 Department of Biology and 2 Department of Psychology, Minot State University, Minot ND

2. Background Environmental variables affect timing of metamorphosis (e.g. temperature, food availability, predator threat). Light and Photoperiod have far reaching effects in all facets of nature (flora and fauna). In the wild, pre-metamorphic Ambystoma tigrinum and A. maculatum are exposed to changing photoperiods.

3. The damselfly, Lestes viridis Rolff et al., 2004, American Naturalist

4. QUESTION ?? Will changing the length of photoperiod in pre-metamorphic tiger and spotted salamanders mimic environmental cues (seasonal change for example) and affect timing of metamorphosis?

5. HYPOTHESIS Manipulating exposure to constant and varying photoperiods in larval Ambystoma tigrinum and A. maculatum will affect timing of metamorphosis.

6. METHODS & PROCEDURE

7. Treatments (X4) L2S All Short All Long S2L

8. Experiment 1

9. Lab Design DOOR Block 3 Block 1 Block 2

10. Feeding

11. RESULTS Morphological traits

12. Morphology Pre-metamorphic Post-metamorphic

13. Metamorphic Timing All ShortS2LL2SAll Long Experiment 1

14. Mass at metamorphosis All ShortS2LL2SAll Long Experiment 1

15. Confounds to a degree?? Temperature variations were +1 ° between Long and Short photoperiods

16. Temp Effects From Hickerson et al., 2005, Southeastern Naturalist Desmognathus quadramaculatus Blackbelly salamander

17. Experiment 2 Methods

18. Metamorphic Timing All ShortS2LL2SAll Long Preliminary Results Experiment 2

19. All ShortS2LL2SAll Long Mass at metamorphosis

20. Versus Discussion: Why the difference? Ambystoma tigrinum Tiger Salamander Ambystoma maculatum Spotted Salamander © 2003 Twan Leenders

21. Further Exploration Experimentation of species with extended larval periods (to include seasonal expanses). Exploration of effects of varying light wavelength on metamorphic timing. Variation in food amount

22. Acknowledgements Amphibian Growth Project team members Claude Ouedraogo Janel Richter Heidi Richter Drew Henry Karew Schumaker Department of Biology