the effects of light cycle on metamorphosis in salamanders kenn rose 1,2 and christopher k. beachy 1...
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The Effects of Light Cycle on Metamorphosis in Salamanders
Kenn Rose 1,2 and Christopher K. Beachy 1
1Department of Biology and 2Department of Psychology, Minot State University, Minot ND
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.
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?
HYPOTHESISHYPOTHESIS
Manipulating exposure to constant and varying photoperiods in larval Ambystoma tigrinum and
A. maculatum will affect timing of metamorphosis.
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light cycle
larval period (days)
Metamorphic Timing
All Short S2L L2S All Long
Experiment 1
Mass at metamorphosis
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light cycle
metamorphic mass (mg)
All Short S2L L2S All Long
Experiment 1
Temp Effects
From Hickerson et al., 2005, Southeastern Naturalist
Desmognathus quadramaculatus
Blackbelly salamander
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High food, hightemp
Low food, hightemp
High food, lowtemp
Low food, lowtemp
Days to metamorphosis
Metamorphic Timing
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light-cycle treatment
larval period (days)
All ShortS2LL2SAll Long
Preliminary Results Experiment 2
Preliminary Results Experiment 2
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light-cycle treatment
metamorphic mass (mg)
All ShortS2LL2SAll Long
Mass at metamorphosis
Versus
Discussion: Why the difference?
Ambystoma tigrinum
Tiger Salamander
Ambystoma maculatum
Spotted Salamander
© 2003 Twan Leenders
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