Variation in Hibernation Expression in Columbian Ground Squirrel (Urocitellus Columbianus) Populations Across Two Elevations
Bibliographic record
Abstract
Hibernation is a physiological adaptation present in many mammals for resource conservation in response to extended periods of environmental shortages. As adaptations are, by definition, only relevant to the environmental conditions to which an individual is exposed, it is reasonable to expect that populations of the same species may exhibit differences in hibernation expression if exposed to different environments. Moreover, such phenotypic variation could be a result of phenotypic plasticity and/or local (genetic) adaptation. Common garden experimental designs—in which individuals from different populations are moved from their native environments into a common environment—can be used to distinguish plasticity from genetic variation. By placing individuals from different populations into a common environment, environmental variation is minimized, which in turn reduces phenotypic plasticity. As a result, any variation that persists between populations under the common environment can be attributed to genetic variation. I investigated how two different free-ranging populations of Columbian ground squirrels (Urocitellus columbianus), varying in elevation, differed in their hibernation expression, and used a common garden experiment to determine whether these differences were the result of phenotypic plasticity and/or local adaptation. I analyzed three years of hibernation data from free-ranging Columbian ground squirrels at both high- and low-elevation sites and collected two years of data from individuals— from both of these elevations— housed under a common laboratory environment. I found significant phenological differences between free-ranging populations. Columbian ground squirrels at high elevations entered hibernation about 11 days later than their low-elevation counterparts, and displayed even more pronounced differences in emergence date, resulting in a longer hibernation period. Individuals at high elevations also exhibited significantly longer torpor bouts than their low-elevation counterparts, but did not differ in the number of torpor bouts or the proportion of time spent in torpor. Both populations achieved similar maximum depths of torpor (i.e., coldest skin temperature recorded), but squirrels at higher elevations experienced greater mean depths of torpor compared to their low-elevation counterparts. When placed under a common environment, individuals from high- and low-elevation sites exhibited very similar hibernation expression, suggesting that the differences observed in free-ranging populations are largely due to phenotypic plasticity.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| 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 source (direct Gemma or distilled Codex), 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".