Geographic variation in energy storage and physiological responses to freezing in the gray treefrogs<i>Hyla versicolor</i>and<i>H. chrysoscelis</i>
Bibliographic record
Abstract
The physiological responses supporting freeze tolerance in anurans are well known, but the evolution of this trait remains little studied. This is the first common-garden study of geographic variation in cryoprotective responses to freezing and the degree of freeze tolerance. We studied the gray treefrogs (Hyla versicolor and H. chrysoscelis) from sympatric sites in Minnesota, Indiana and Missouri. Patterns in the literature suggest that northern frogs produce more cryoprotectants upon freezing, but we found no geographic variation in cryoprotective responses or degree of freeze tolerance. The concentration of glucose produced upon freezing was higher than previously reported for this species (liver: 475 micro mol g(-1) dry mass). Unfrozen frogs had high levels of glycerol (liver: approx. 150 micro mol g(-1) dry mass), and did not produce more upon freezing. Liver glycogen content (concentration multiplied by liver mass) was highest in frogs from Minnesota and Missouri, and was stored in preference to lipids in Minnesota frogs, possibly to provide energy for the longer northern winters. Minnesota frogs accumulated more ice (53.4+/-1.8%) after freezing to-2.5 degrees C than Indiana frogs (45.5+/-3.3%). The two species differed in body size but not in any of the physiological parameters measured. We conclude that these populations show no adaptive variation in freeze tolerance and that comparing published studies may be misleading because of different acclimation and feeding regimes.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".