Dynamic and asynchronous ontogenetic changes in growth and metabolic rate in thirteen-lined ground squirrels (<i>Ictidomys tridecemlineatus</i>)
Bibliographic record
Abstract
As mammals grow from developmentally immature neonates into adults, metabolic rate (V̇O2) has been hypothesized to scale isometrically with body mass until individuals reach a critical size, after which scaling becomes hypometric. This study aimed to determine when this occurs and gain insight into why this metabolic switch occurs in altricial thirteen-lined ground squirrels (Ictidomys tridecemlineatus). We hypothesized that the switch would be related to patterns of growth and development. We measured the mass and resting V̇O2 of I. tridecemlineatus pups using flow-through respirometry at postnatal days (P)0-P30 (inclusive), P60, P90, P120 and at over 1 year old and found repeated and asynchronous ontogenetic changes in growth rate and metabolic scaling. Following birth, pups grew 1.18±0.02 g day-1 and metabolism scaled isometrically as predicted (scaling exponent B=1.01±0.03). Surprisingly, B more than doubled to 2.64±0.13 at P18-P23 while growth rate remained constant. At P29, growth rate more than quadrupled to 4.87±0.03 g day-1 while between P35 and P43 the further increase in V̇O2 was proportionately less, and thus B fell to -0.27±0.43. Adult size was reached by P79, with final scaling and growth rate values maintained into adulthood (P465). The asynchronous changes in mass and resting V̇O2 appear to reflect metabolic trade-offs as pups allocated energy towards physiological development (P18-P35) versus growth (P35-P79): the period of hypermetabolic scaling (B=2.64±0.13) coincided with the time when pups became weaned and sufficiently physiologically and morphologically developed to live independently.
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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 | 0.000 | 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) | 0.001 | 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".