Stable Isotopes Link Diet to Avian Yolk Carotenoid Allocation: A Comparative Study of Five Auk Species (Charadriiformes: Alcidae)
Bibliographic record
Abstract
The allocation of important but environmentally limited nutrients, such as carotenoids, often represents a trade-off between homeostasis and reproduction. However, key questions remain about how diet and species traits influence carotenoid allocation. We studied yolk carotenoid profiles and yolk color in relation to trophic level (based on delta(15)N values) in five species of seabirds belonging to the family Alcidae: common murre (Uria aalge), pigeon guillemot (Cepphus columba), Cassin's auklet (Ptychoramphus aleuticus), rhinoceros auklet (Cerorhinca monocerata), and tufted puffin (Fratercula cirrhata). In three species, which ranged from low (tufted puffin) to high (pigeon guillemot) trophic level, yolks had pink to red hues and contained exclusively astaxanthin, while yolks of species from a high trophic level (common murre) and from a generalist forager (rhinoceros auklet) had yellow to orange hues and contained astaxanthin, lutein, and zeaxanthin. The absence of a systematic relationship between trophic level and carotenoid types suggests that these species possess adaptations for the uptake and use of specific carotenoids. In contrast, total yolk carotenoid concentrations were best explained by the combination of species and trophic level: lower-trophic-level feeding was linked to production of carotenoid-rich yolks, both across species and within the one generalist species. We conclude that both behavioral and physiological traits can play strong roles in the acquisition and allocation of critical nutrients from mothers to their offspring.
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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 | 0.000 | 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".