scholarly journals Future winters present a complex energetic landscape of decreased costs and reduced risk for a freeze‐tolerant amphibian, the Wood Frog ( Lithobates sylvaticus )

2020 ◽  
Vol 26 (11) ◽  
pp. 6350-6362 ◽  
Author(s):  
Megan J. Fitzpatrick ◽  
Warren P. Porter ◽  
Jonathan N. Pauli ◽  
Michael R. Kearney ◽  
Michael Notaro ◽  
...  
Keyword(s):  
Wood Frog ◽  
Lithobates Sylvaticus ◽  
Freeze Tolerant ◽  
Reduced Risk

Freeze-thaw injury in erythrocytes of the freeze-tolerant wood frog, Rana sylvatica

1991 ◽  
Vol 261 (6) ◽  
pp. R1346-R1350 ◽  
Author(s):  
J. P. Costanzo ◽  
R. E. Lee
Keyword(s):  
Cell Injury ◽  
Osmotic Fragility ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Wood Frog ◽  
In Vitro Tests ◽  
Freezing And Thawing ◽  
Freeze Tolerant ◽  
High Concentrations

Erythrocytes from the freeze-tolerant wood frog (Rana sylvatica) were subjected to in vitro tests of freeze tolerance, cryoprotection, and osmotic fragility. The responses of cells from frogs acclimated to 4 or 15 degrees C were similar. Erythrocytes that were frozen in saline hemolyzed at -4 degrees C or lower. The addition of high concentrations (150 and 1,500 mM) of glucose or glycerol, cryoprotectants produced naturally by freeze-tolerant frogs, significantly reduced cell injury at -8 degrees C, but concentrations of 1.5 or 15 mM were ineffective. Hemolysis was reduced by 94% with 1,500 mM glycerol and by 84% with 1,500 mM glucose; thus glycerol was the more effective cryoprotectant. Mean fragility values for frog erythrocytes incubated in hypertonic and hypotonic saline were 1,938 and 49 mosM, respectively. Survival in freeze tolerance and cryoprotection experiments was comparable for erythrocytes from frogs and humans, suggesting that these cells may respond similarly to freezing-related stresses. However, the breadth of osmotic tolerance, standardized for differences in isotonicity, was greater for frog erythrocytes than for human erythrocytes. Our data suggest that erythrocytes from R. sylvatica are adequately protected by glucose under natural conditions of freezing and thawing.

Enzymatic regulation of seasonal glycogen cycling in the freeze-tolerant wood frog, Rana sylvatica

2016 ◽  
Vol 186 (8) ◽  
pp. 1045-1058 ◽  
Author(s):  
M. Clara F. do Amaral ◽  
Richard E. Lee ◽  
Jon P. Costanzo
Keyword(s):  
Rana Sylvatica ◽  
Wood Frog ◽  
Enzymatic Regulation ◽  
Freeze Tolerant

Influence of prey diet quality on predator-induced traits in wood frog tadpoles (Lithobates sylvaticus)

2021 ◽  
pp. 1-11
Author(s):  
Catherine Chuirazzi ◽  
Melissa Ocampo ◽  
Mizuki K. Takahashi
Keyword(s):  
Predation Risk ◽  
Diet Quality ◽  
Growth And Development ◽  
Chemical Cues ◽  
Wood Frog ◽  
Experimental Conditions ◽  
Lithobates Sylvaticus ◽  
Phenotypic Changes ◽  
Intestinal Length ◽  
Frog Tadpoles

Abstract Diet quality and predation are two critical factors in determining the growth and development of organisms. Various anurans are susceptible to phenotypic changes influenced by these factors. Yet, few studies examined prey diet quality as potential influence over predator-induced traits. Using wood frog tadpoles (Lithobates sylvaticus) as a model species, we investigated the effects of three diet compositions (plant-based, animal-based, omnivorous) crossed with presence or absence of chemical cues from predatory dragonfly larvae (Aeshnidae). After 35 days, we recorded 11 morphological measurements, Gosner stage, and intestinal length of tadpoles to assess phenotypic changes under the six different experimental conditions. Our results showed the additive effects of both diet quality and predator chemical cue without detection of interactions between the two. Tadpoles receiving the omnivorous diet grew and developed faster with wider denticle rows than those receiving the plant or animal diets. The growth and development of tadpoles receiving only the animal diet were significantly hindered. These results emphasize the importance of diet quality in the growth and development of larval wood frogs. Chemical cues from predators significantly reduced tadpole body size but, in contrast to previous findings, did not affect tail size. Our experimental procedure of providing water containing predator and injured conspecific chemical cues on a weekly basis likely provided relatively weak predation risk perceived by tadpoles compared to previous studies using caged predators. The predator environment in our experiment, however, represents one ecologically relevant scenario in which predation risk is not urgent.

scholarly journals Time-dependent latent inhibition of predator-recognition learning

2019 ◽  
Vol 15 (5) ◽  
pp. 20190183 ◽  
Author(s):  
Adam L. Crane ◽  
Douglas P. Chivers ◽  
Maud C. O. Ferrari
Keyword(s):  
Predation Risk ◽  
Latent Inhibition ◽  
Learning Opportunities ◽  
Predator Recognition ◽  
Wood Frog ◽  
Time Dependent ◽  
Negative Consequences ◽  
Lithobates Sylvaticus ◽  
Frog Tadpoles ◽  
Recognition Learning

To optimally manage an environment with predators, prey must correctly distinguish between cues that are risky and cues that are safe. Even a specific cue that is safe in one area or at a certain time may be dangerous in other situations, and vice versa. Latent inhibition is a cognitive mechanism by which animals fail to learn that a stimulus as risky because they have already learned it as non-threatening via previous encounters with the stimulus in the absence of negative consequences. Here, we demonstrate that latent inhibition of predator-recognition learning in wood frog tadpoles, Lithobates sylvaticus , depends on the timing of their learning opportunities. For 6 days, tadpoles were exposed daily to an initially novel stimulus (salamander odour), either in the morning (11.00–13.00 h) or evening (16.00–18.00 h). The following day, we conditioned tadpoles to recognize the salamander odour as a predator by pairing it with injured tadpole cues, either at the same time as their previous experience or at the opposite time. When tested the following day, latent inhibition occurred under each scenario where the timing of conditioning matched the timing of the pre-exposure. However, tadpoles tested in the morning showed learned fright responses when conditioned in the morning if their pre-exposure had occurred in the evening, whereas individuals tested in the evening showed learned fright responses when conditioned in the evening if their pre-exposure had occurred in the morning. This is the first report of time-dependent latent inhibition of predator-recognition learning, which is likely an important mechanism for correctly managing predation risk and safety.

Regulation of pyruvate kinase from muscle of Freeze tolerant wood frog, Rana sylvatica

Cryobiology ◽  
2016 ◽  
Vol 73 (3) ◽  
pp. 437
Author(s):  
J. Mattice ◽  
M. Smolinski ◽  
K. Storey
Keyword(s):  
Pyruvate Kinase ◽  
Rana Sylvatica ◽  
Wood Frog ◽  
Freeze Tolerant
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